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The mode of inheritance of the bareback characteristics in Rhode Island red chicks Hill, Stanley Robert Garbott 1950

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THE  MODE  0 F 0 F  B A R E B A C K  I N H E R I T A N C E THE  C H A R A C T E R I S T I C I N  R H ODE  I S L A N D  RED  C H I C K S by Stanley R. G. H i l l  A Thesis Submitted i n p a r t i a l f u l f i l m e n t of requirements f o r the degree of MASTER OF SCIENCE IN AGRICULTURE  i n the Department  of Poultry Husbandry  The U n i v e r s i t y of B r i t i s h Columbia A p r i l , 1950  (Zcc^itCd,  THE mm  Off IKHERITAHCE Off THE BAREBACK CHARACTERISTIC IN RHODE ISLAHD RED CHICKS AH ABSTRACT  Experimental work was undertaken i n an e f f o r t to d i s cover the p o s s i b l e genetic cause of the poor f e a t h e r i n g q u a l i t y of back f e a t h e r i n g f r e q u e n t l y encountered i n the Rhode I s l a n d Red breed of domestic fowl which c h a r a c t e r i s t i c had severely m i l i t a t e d against t h i s p a r t i c u l a r "breed w i t h the r a p i d l y grownig importance of the b r o i l e r aspect of the poultry industry. f e a t h e r i n g data on the 1948 and 1949 hatches of the'UBC s t r a i n are presented and analyzed i n t h i s l i g h t .  Data on ex-  perimental matings, i n v o l v i n g "bareback" Rhode I s l a n d Red s i r e s mated to "bareback" Rhode I s l a n d Red dams, to slowf e a t h e r i n g Barred Plymouth Rock and Hew Hampshire dams and to homozygous e a r l y - and normal-feathering "White Leghorns, are treated i n a l i k e manner. C  Consequent to the observations made and deductions drawn,  the w r i t e r p o s t u l a t e s a "Theory of I n h i b i t o r s " as an exp l a n a t i o n of t h i s unfavourable f e a t h e r i n g aspect of the Rhode I s l a n d Red.  Four f a c t o r s are b e l i e v e d to be involved.  The  experimental work presented was i n s u f f i c i e n t to demonstrate whether three of these - one "major" and two "minor" i n h i b i t o r s - were s e x - l i n k e d or autosomal i n nature, while the f o u r t h appeared to act as a sex-linked r e c e s s i v e gene.  The  major i n h i b i t o r apparently d i d not f i n d expression i n the Rhode I s l a n d Red and was assumed to c o n s t i t u t e a normal  complement of the Rhode Island Red*s c h a r a c t e r i s t i c type of feathering.  In inter-breed matings, however, i t appeared to  be dominant to normal Leghorn f e a t h e r i n g i n suppressing t a i l development.  The two minors, i n cumulative a c t i o n w i t h  the  major, were b e l i e v e d to be responsible f o r the v a r i a t i o n s i n secondary f l i g h t and t a i l feather development observed i n Rhode I s l a n d Red  chicks.  The sex-linked recessive gene apparently gave r i s e to a retarded type of back f e a t h e r i n g , which e f f e c t was  observed  to extend p o s t e r i o r l y to s i m i l a r l y r e t a r d the development of the c e n t r a l t a i l feathers and,  i n conjunction w i t h the major  i n h i b i t o r or the two minor i n h i b i t o r s , was p r i m a r i l y responsible f o r the "bareback" c o n d i t i o n . Further experimental work was  i n d i c a t e d to d e f i n i t e l y  prove t h i s hypothesis and to a s c e r t a i n the mode of inheritance of the genes involved.  ACKNOV/LEDGEMENT  The writer wishes to express his indebtedness to Professor E. A. Lloyd, Head of the Department, f o r his h e l p f u l suggestions and co-operation throughout the past two years i n carrying out t h i s work. To Miss Mary Philpot, whose s i n cere interest i n the subject and a s s i s t ance i n the preparation of the report are r e f l e c t e d to a large degree i n t h i s paper, g r a t e f u l acknowledgement i s also extended.  Table of Contents  Introduction  1.  Review of Literature  6.  The UBC S t r a i n of Rhode Island Reds History  18.  Method of Feather C l a s s i f i c a t i o n .. 22. Observations - UBC Farm Flock 1948 Data  25.  1949 Data  38.  Observations - Experimental Matings Mating 1  49.  Mating 2  57.  Mating 3  65.  Discussion  78.  Conclusions  81.  Bibliography  83.  Appendix  The Mode of Inheritance of the Bareback Characteristic i n Rhode Island Red Chicks Introduction The importance of early- and f u l l - f e a t h e r i n g i n the domestic fowl has been emphasized by the recent phenomenal increase on t h i s continent i n the demand f o r the f r y i n g type of chicken.  This market adaptation underwent a "mushroom"  growth during the war and has continued to grow during the intervening years. While the b r o i l e r and f r y e r types of chickens are defined i n terms of weight-^-, consistent with a well-fleshed carcass, such terms can, by transposition, be defined with f a i r accuracy i n terms of age with regard to any s p e c i f i c breed. Thus, a marketable  f r y i n g chicken must be f u l l y feathered by  twelve weeks of age and comparatively free of pin feathers i n order to meet the desired l e v e l of quality i n dressing.  Even  younger birds are required to s a t i s f y variations i n demand, which factor i s of particular importance with the heavier breeds. This trend i n demand has induced the poultry breeder to give closer attention to the feathering q u a l i t i e s of h i s flock.  As a r e s u l t , the slow-feathering breeds, such as the  1. Canadian s p e c i f i c a t i o n s , as set f o r t h i n the "Regulations Made Under the Provisions of the Live Stock and Live Stock Products Act, Chapter 120 of the Revised Statutes of Canada. 1927, Respecting the Grading and Marking of Dressed Poultry, as published i n the Canada Gazette, November 19, 1928, and Incorporated Amendments i n the Canada Gazette. December, 1931, and November, 1934" are as follows: (the dozen. Squab B r o i l e r s : Young chickens not more than 19 l b s . to B r o i l e r s : Young chickens not more than 28 l b s . to the dozen. Fryers: Chickens from 29 l b s . to 42 l b s . to the dozen.  Rhode Island Red and the Barred Plymouth Rock, and more p a r t i c u l a r l y c e r t a i n strains of these breeds, have suffered considerably  i n popularity with poultry breeders i n spite  of t h e i r other favourable  economic c h a r a c t e r i s t i c s .  In considering r a p i d i t y of feathering, i t should be borne i n mind that the f i r s t quarter of t h i s century s t i l l the era of the poultry fanciers who  was  were not con-  cerned with t h i s p a r t i c u l a r c h a r a c t e r i s t i c i n t h e i r b i r d s . Insofar as plumage was  ooncerned the factors of color and  color pattern were indeed of primary importance but, as the interests of these breeders lay s o l e l y i n the production exhibition birds, there was  no significance attached  time element required i n reaching these objectives.  of  to the Thus,  while the f i r s t p r i n c i p l e adopted by the American Poultry 2 Association was "that i n each breed then e x i s t i n g the most 3 useful type should be made the Standard type",  i t should  be remembered that the word "useful" did not carry then the economic implications which are now  automatically  accepted  i n the l i g h t of the present market demand for poultry products.  The f a c t that the Mediterranean breeds, symbolized  i n America c h i e f l y by the White Leghorn, were rapid feathering and that the heavier breeds, including both the Americans and A s i a t i c s , were generally slow feathering given no o f f i c i a l recognition whatsoever.  was  S i m i l a r l y , the  2. Organized by the poultry breeders i n 1873  at Buffalo,  N.Y.  3. The American Poultry Association, Inc., The American Standard of Perfection. Davenport, Iowa, Published by the editors, revised edition, 1945, p. 6.  productive capacity of any breed did not concern the association.  While both of these c h a r a c t e r i s t i c s were l e f t  s o l e l y with the d i s c r e t i o n of the i n d i v i d u a l breeder i n the development of h i s p a r t i c u l a r s t r a i n , i t required the demands of a commercialized poultry industry to focus attention upon t h e i r economic value.  The growing importance of t h i s aspect  was accompanied by the establishment of annual egg-laying contests throughout the United States.  During t h i s period  certain breeders of the American breeds, notably the Rhode Island Red, were highly successful i n disproving the widelyaccepted supposedly-inherent poor laying q u a l i t i e s of these breeds.  Through t h e i r e f f o r t s the overriding importance of  s t r a i n rather than breed has been firmly established, with the r e s u l t that the Rhode Island Red i s today the main contender to the White Leghorn i n these contests. While the consumption of poultry meat i n the form of b r o i l e r s and fryers has undergone a phenomenal increase, attention must also be given to the f a c t that the demands f o r mature birds as roasting chicken have also r i s e n considerably.  Undoubtedly this was occasioned primarily by the  shortage of red meats during the war years, but i t s e f f e c t i n popularizing roast chicken on the average American menu has continued to enjoy an increasing trend.  As an answer -GO  T#he combined market demands f o r ooth eggs ana poultry meat, breeders began to devote more of t h e i r attention to the American breeds which had been developed o r i g i n a l l y to meet such a dual purpose.  Within t h i s group the Rhode Island Red,  which arose from Red Malay Game, Leghorn and A s i a t i c ancestry, became p a r t i c u l a r l y popular.  This has resulted  i n c e r t a i n strains of t h i s breed being second to none i n the production of roasting poultry meat. Recognition of the commercial importance of b r o i l e r and f r y e r production became p u b l i c l y evident with the holding 4 of the "Chicken of Tomorrow" contest i n the United States during the years 1946-48 i n c l u s i v e . The r e s u l t s of t h i s contest showed the Rhode Island Red to be conspicuously 5  absent.  In view of i t s valuable dual productive q u a l i t i e s  noted above, i t scarcely needs mentioning that i t s slow feathering c h a r a c t e r i s t i c , p a r t i c u l a r l y the widespread poor quality of i t s back feathering, severely m i l i t a t e d against i t s choice by the breeders s t r i v i n g f o r acclaim i n t h i s contest. The demise of the important role of the poultry f a n c i e r was accompanied, and to a large extent accounted f o r , by the r i s e of the science of genetics i n general, and, i n p a r t i c u l a r , by the increase i n the knowledge of the heritable c h a r a c t e r i s t i c s which determine the production r e s u l t s which can be expected subsequently i n the poultry 4. Sponsored by the Great A t l a n t i c and P a c i f i c Tea Company primarily as an incentive towards the production of better 12-week-old f r y i n g chicken. This objective was stressed e n t i r e l y during the f i r s t year, to a lesser extent i n 1947, while other f a c t o r s were given consideration also i n 1948, mainly egg production, v i a b i l i t y and feed e f f i c i e n c y . 5. At least within the f i r s t eight leading entries which the writer saw published.  - 5 flock.  Progress i n t h i s f i e l d , and i n the f i e l d of  n u t r i t i o n , has contributed g r e a t l y to the continued  increase  i n productive capacity i n terms of both eggs and meat.  The  importance of the r o l e played by a b i r d ' s genetic cons t i t u t i o n being thus accepted, a genetic approach towards s o l v i n g the f e a t h e r i n g problem, posed by the recent t r a n s i t i o n a l trend i n the demands of the p o u l t r y market, i s not only l o g i c a l but w e l l j u s t i f i e d .  However, i n s p i t e of  considerable research work which has been conducted i n an e f f o r t t o overcome the i n f e r i o r f e a t h e r i n g q u a l i t y of the Rhode I s l a n d Red,  the persistence of the.-"bareback" s t i l l  remains as a widespread disparaging c h a r a c t e r i s t i c of t h i s breed.  I n t h i s regard the U n i v e r s i t y of B r i t i s h Columbia  s t r a i n has not remained immune. 6. Punnett, i n the preface to h i s book Heredity i n P o u l t r y , c i t e s that "happily there are signs that the p o u l t r y i n d u s t r y is.beginning t o recognize the p r a c t i c a l value of organized research, and i t i s i n the hope of s t i m u l a t i n g that r e c o g n i t i o n that I have t r i e d to summarize our present knowledge, meagre though i t i s . " Dated Cambridge, Dec. 1922. The MacMillan Co. of Can. L t d . , Toronto, 1923.  Review of Literature Investigation of the genetic c o n s t i t u t i o n of the domestic fowl, insofar as i t concerns the rate of feathering, was  f i r s t reported by Serebrovsky (1922).  Working with Russian O r l o f f s and Barred Plymouth Rocks, he demonstrated the presence of a sex-linked gene i n the l a t t e r breed which "retards development of feathering i n the chicks, so that at the age of 1 to 1.5 months they 7  have very small t a i l s . " was  Development of f l i g h t feathers  also noted to be "very slow". Warren (1925) noted that Leghorn chicks showed t a i l  development by the ninth day at the l a t e s t , while no Jersey Giant chicks showed similar development by the s sixteenth day with a large majority of them lacking such growth u n t i l the t h i r t i e t h or thirty-seventh day observations  were made after the ninth day).  (weekly  Reciprocal  matings and back crosses demonstrated the dominance of the slow feathering c h a r a c t e r i s t i c of the Jersey Giant over the rapid feathering of the Leghorn and also that the genes responsible were sex-linked. Kinugawa (1927) presented evidence to show that Leghorns, Minorcas, Hamburgs and Nagoyas were c h a r a c t e r i s t i c a l l y early feathering because they possessed i n homozygous condition the recessive sex-linked a l l e l e . Hays and Sanborn (1942) c i t e that "Saharova (1926) 7. Serebrovsky, A.S., "Crossing-over Involving Three Sexlinked Genes i n Chickens", Amer. Nat., 56:571-572, 1922. 8. Loc. c i t .  - 7 -  c a l l e d a t t e n t i o n to sex d i f f e r e n c e s i n the r a t e of f e a t h e r i n g of the general purpose breeds, to the slow f e a t h e r i n g i n the A s i a t i c breeds, and to the r a p i d f e a t h e r i n g i n the Mediterranean breeds.  He i n d i c a t e d t h a t  the dimorphic type of f e a t h e r i n g was dominant over r a p i d Q  f e a t h e r i n g , was not s e x - l i n k e d but was sex l i m i t e d . "  The  dimorphic type of f e a t h e r i n g which he noted, whereby the females tend to f e a t h e r more r a p i d l y than the males, has been corroborated by many i n v e s t i g a t i o n s regarding the American breeds.  Among these has been the work of M a r t i n  (1929) d e a l i n g w i t h Barred Plymouth Rocks, Radi and Warren (1938) and Hays and Sanborn (1942) w i t h Rhode I s l a n d Reds, Darrow and Warren (1944) w i t h both White and Barred Plymouth Rocks and Rhode I s l a n d Reds and G-lazener and J u l l (1946) w i t h Barred Plymouth Rocks and New  Hampshires.  S e v e r a l i n v e s t i g a t i o n s i n t h i s f i e l d have a l l demons t r a t e d the dominance of the l a t e - f e a t h e r i n g s e x - l i n k e d gene (now known as K) over i t s e a r l y - f e a t h e r i n g a l l e l e ( k ) . Mediterranean breeds appear to be normally homozygous f o r " e a r l y " and much c r e d i t has been given to such possession of t h i s gene i n appraising the s u p e r i o r i t y of the "Leghorn type" of f e a t h e r i n g over that u s u a l l y encountered w i t h the heavier b i r d s , i n c l u d i n g the American breeds.  However,  while no research work has ever shown the possession of t h i s gene i n homozygous form to be other than b e n e f i c i a l , i t i s 9. Saharova, L.N., g e n e t i c s of the Rate of F e a t h e r i n g , e d i t e d by K o l t z o f f , 1926, p. 130. Quoted from Hays, F.A. and Sanborn, R., Breeding Rhode I s l a n d Reds For Rapid F e a t h e r i n g , Mass. A g r i c . Expt. S t a . B u l l e t i n No. 396, p. 2.  open to question whether i t has merited i n i t s entirety the degree of importance given to i t by some investigators i n securing rapid f u l l n e s s of feathering.  In t h i s regard, Jaap  and Morris (1937) noted that "Warren (Payne and Scott, 1 9 3 4 )  10  by use of the sex-linked gene f o r early t a i l and wing feathering, has been able to produce a s t r a i n of Rhode Island Reds which feather out ' l i k e Leghorns'.  While t h i s may  simplest s o l u t i o n to the feathering problem i t may  be the  be i n -  t e r e s t i n g to note that the rapid-feathering Buff Orpingtons previously discussed contain very few, i f any,  sex-linked  rapid feathering i n d i v i d u a l s . " Reference i s made here to 1 1  a s t r a i n of Buff Orpingtons, data on which were omitted from t h e i r caluulations regarding the influence of various factors on the rate of feathering, because they "were p r a c t i c a l l y 12 a l l well feathered at eight weeks of age".  I t should  be  noted i n passing that the U n i v e r s i t y of B r i t i s h Columbia s t r a i n of New  Hampshires also exhibits t h i s c h a r a c t e r i s t i c  to a high degree, i . e . , early f u l l n e s s of feathering but not early feathering i n the sense implied by the possession  of  the early-feathering gene i n homozygous form. Danforth (1929), by means of skin transplantation on newly-hatched chicks, produced evidence of there being two 10. Payne, L.F. and Scott, H.M., International Poultry Guide f o r Flock S e l e c t i o n , International Baby Chick Association, Kansas C i t y , Missouri, 1934. 11. Jaap, R.G. and Morris, L. Genetic Differences i n Eightweek Weight and Feathering. Poultry Science 16: p. 47.(1937). 12. Loc. c i t .  - 9 e n t i r e l y d i f f e r e n t factors capable of producing slow feathering i n the young chick, one sex-linked, the other autosomal.  Aside from these conclusions, however, their  data were i n s u f f i c i e n t to indicate the exact mode of inheritance involved. Rhode Island Reds apparently possessed only the sex-linked gene, while Barred Plymouth Rocks possessed both. Warren (1933) reported a modifying autosomal gene i n White Leghorns which inhibited the development of t a i l feathers and some of the secondary f l i g h t feathers.  He  termed the gene "retarded", and showed evidence of i t being recessive to normal feathering. Because of the greater retardation i n feather development r e s u l t i n g from the presence of the dominant sex-linked late-feathering gene, the expression of "retarded" became masked when both of the genes were present i n the i n d i v i d u a l . Radi and Warren (1938) developed three strains of Rhode Island Reds, the f i r s t of which was homozygous f o r the sexlinked early-feathering gene, while the other two were homozygous f o r the dominant a l l e l e .  By seleotion within  the early-feathering s t r a i n , they succeeded i n producing chicks of both sexes which were p r a c t i c a l l y f u l l y feathered at four weeks of age "much l i k e ordinary Leghorns".  Using  13. Radi, M.H., and Warren, D.C, "Studies on the Physiology and Inheritance of Feathering i n the Growing Chick", Journal of A g r i c u l t u r a l Research. 1938, V o l . 56, p. 695.  - 10 extremes i n the extent of back feathering as a basis of selection, they attempted to e s t a b l i s h two late-feathering 14  s t r a i n s which they c a l l e d "well-feathering" feauhering". incompletely former was  and "poor-  Tney concluded "Gnat "well-feathering" dominant to "poor-feathering",  was  and tnat the  conditioned by autosomal f a c t o r s .  The  s i m i l a r i t y of r e s u l t s of r e c i p r o c a l orosses did not indicate tne  presence or any important sex-liniced ractora oeing  responsible ror the dirrerence i n the  genetic constitutions  or the two s t r a i n s . Lloyd (1939) observed varying aegrees ox  reathering  i n Rhode Island Reds, Barred Plymouth Rocks, Cambars and lAlhite Leghorns at four, s i x and eight weeks of age. observations  His  would seem to indicate the dominance of early  14. In order to avoid misunderstanding of the phenotypic descriptions involved i n the terms "well-feathering" (as used here by Warren) and " f u l l - f e a t h e r i n g " (as used throughout t h i s paper), i t should be noted that they do not bear s i m i l a r connotation. "While the l a t t e r permits a l i t e r a l interpretation i n i t s ent i r e t y , the former allows such interpretation only i n the narrow sense of opposition to "poorfeathering" as used here also by Warren. While his use of the term "well-feathering" would, therefore, seem to constitute a decided misnomer i n the l i g h t of the present demand f o r early f u l l n e s s of back feathering, i t i s to be remembered that such emphasis i s of comparatively reoent o r i g i n and that at the time Warren's paper was prepared the "bareback" constituted what could probably be stated to be the normal condition of the Rhode Island Red at the b r o i l e r age.  - i l ls feathering  i n some s t r a i n s of Rhode I s l a n d Reds.  I t i s of  i n t e r e s t to note that the male b i r d , used i n these f i n d i n g s , was secured from one of the f a m i l i e s of the McRae (Milwaukie, Oregon) s t r a i n i n which the males were as w e l l feathered as the females at four weeks of age.  Such males appeared "to be  'hen-feathered' with long t a i l feathers s i m i l a r to those of the p u l l e t s " ,  and showed "an amount and length of f e a t h e r i n g  over the breasts, backs, and thighs equal t o that found on 17  the p u l l e t chicks of the same age."  From the d e s c r i p t i o n  given, i t would appear that i n the development of at l e a s t some of the f a m i l i e s of the McRae s t r a i n the normal dimorphic f e a t h e r i n g of the American breeds had been l o s t , and that t h i s aspect of t h e i r genetic c o n s t i t u t i o n exerted a dominant i n f l u e n c e over dimorphism.  I f this interpretation i s correct,  such f i n d i n g s are c e r t a i n l y at variance w i t h f e a t h e r i n g 15. I t i s t o be noted t h a t , during the l a s t f i f t e e n years, the term " e a r l y f e a t h e r i n g " has been v a r i o u s l y used as d e s c r i p t i v e terminology i n reports r e l a t i v e to the f e a t h e r i n g c h a r a c t e r i s t i c s of the domestio f o w l . I n some cases, such as here, reference i s a c t u a l l y made to what may more s p e c i f i c a l l y be c a l l e d " e a r l y f u l l n e s s of f e a t h e r i n g " r a t h e r than the narrower meaning, f o r which i t i s now reserved, of the expression of the r e c e s s i v e s e x - l i n k e d gene (k) i n well-developed primary f l i g h t feathers of the 1-day-old c h i c k and, presumably, i n the prominent t a i l feathers of the 10-day-old c h i c k . As f u l l n e s s of f e a t h e r i n g appears to be governed by autosomal genes, at l e a s t i n s o f a r as past research has been able to show, i t i s advisable to bear t h i s f a c t i n mind as an explanation to what otherwise may appear t o be c o n f l i c t i n g r e s u l t s of research i n t h i s f i e l d . 16. L l o y d , E.A., "Breeding f o r Egg and Meat Production", P r o o l Seventh World's P o u l t r y Congress and E x p o s i t i o n . Cleveland, Ohio, 1939, p. 484. 17. Loc. c i t .  - IE c h a r a c t e r i s t i c s u s u a l l y encountered w i t h t h i s breed. Darrow (1941) made observations  on heavy b i r d s showing  possession of the s e x - l i n k e d , e a r l y - f e a t h e r i n g gene and found " a f a i r l y high c o r r e l a t i o n between the numbers and lengths of secondary wing feathers and the degree of development of 18  the t a i l f e a t h e r s , a t ten days of age."  He states t h a t  "a strong tendency e x i s t s f o r the day-old chick having the greater number and length of secondary wing feathers t o be 19 b e t t e r feathered a t the b r o i l e r age."  Observations made i n  t h i s (the w r i t e r ' s ) experiment corroborated intrabreed matings.  t h i s tendency w i t h  However, when a bare-backed male was used  i n interbreed matings, such a tendency,,while holding w i t h i n each of the two r e s u l t i n g broad groups (based upon j u v e n i l e t a i l development), d i d not apply t o the hatch as a whole.  Darrow  f u r t h e r states that "probably the highest c o r r e l a t i o n i s between a well-developed 6 weeks of age."  t a i l at 10 days and good back f e a t h e r i n g a t 20 Here, again, observations made by the w r i t e r  n e c e s s i t a t e m o d i f i c a t i o n of t h i s conclusion t o apply only t o the progeny of intrabreed matings.  Results obtained from i n t e r -  breed matings i n v o l v i n g a bare-backed male show t h a t , while a l l the progeny having good t a i l development a t ten days possess good back f e a t h e r i n g a t s i x weeks, the reverse c e r t a i n l y does not hold t r u e . 18. Darrow, M.I., " R e l a t i o n of Day-old Chick Wing Feather Development t o Feathering a t the B r o i l e r Age", P o u l t r y Science. 1941, V o l . 20, p. 458. 19. Loo. c i t . 20. Loo, c i t .  - 13 MoGlary and Bearse (1941) reported a recessive autosomal gene i n White Leghorns which was found t o r e t a r d normal feathering.  As t h i s f a c t o r was "expressed i n the absence of  a l l t a i l feathers and secondary wing feathers, and slow growth of primaries and body feathers u n t i l the chicks are 21 four to s i x weeks of age",  i t would seem u n l i k e l y that t h i s  could be the same as the "retarded" gene reported by Warren, as the degree of r e t a r d a t i o n of feather development reported i n t h i s paper was of greater s e v e r i t y . Hays and Sanborn (1942) presented t h e i r r e s u l t s of ten years' s e l e c t i o n and breeding f o r improvement of back f e a t h e r i n g i n Rhode I s l a n d Reds.  By s e l e c t i o n on the b a s i s of  the c o n d i t i o n of back f e a t h e r i n g only, at eight weeks of age, progress had been p o s i t i v e but slow. The study i n d i c a t e d the p o s s i b i l i t y of a c c e l e r a t i n g the r a t e of improvement by r e s t r i c t i n g t h i s method of s e l e c t i o n t o only those b i r d s which showed t a i l development at ten to twelve days of age.  They  concluded t h a t , i n a d d i t i o n to the recessive sex-linked e a r l y f e a t h e r i n g gene, there was a dominant autosomal gene f o r b e t t e r f e a t h e r i n g which acted i n a cumulative manner w i t h the former to give complete back f e a t h e r i n g a t eight weeks of age. Darrow and Warren (1944) elaborated upon the previous study by Darrow (1941) and i n v e s t i g a t e d the extent of the c o r r e l a t i o n between f l i g h t feather development and the degree 21. McClary, C.F. and Bearse, G.E., "Recessive Autosomal Factor f o r Slow Plumage Development i n the Chick", P o u l t r y Science, 1941, V o l . 20, p. 466.  - 14 of f e a t h e r i n g at the b r o i l e r age.  They noted that " i n sex-  l i n k e d e a r l y f e a t h e r i n g b i r d s there are many v a r i a t i o n s i n the 22 degree of f e a t h e r i n g . "  I n a d d i t i o n to the above, they under-  took a study of "the nature of the h e r i t a b l e f a c t o r s involved 23 i n b r i n g i n g about the d i f f e r e n c e s i n degree of f e a t h e r i n g . " The c o r r e l a t i o n between 10-day t a i l development and 6- and week back f e a t h e r i n g was the highest obtained  8-  i n t h i s study,  and they concluded that t a i l development a t 10 days was  a  valuable c h a r a c t e r i s t i c f o r p r e d i c t i o n of primary f e a t h e r i n g . They a l s o obtained a h i g h l y s i g n i f i c a n t c o r r e l a t i o n between the number of day-old secondaries t o 10-day t a i l development and to 6- and 8-week back f e a t h e r i n g .  The c o r r e l a t i o n between  both the number and the length of day-old primaries to 10-day t a i l development and to 6- and 8-week back f e a t h e r i n g , while s t a t i s t i c a l l y s i g n i f i c a n t , was not s u f f i c i e n t l y so to form a r e l i a b l e b a s i s of p r e d i c t i o n .  A s i m i l a r c o r r e l a t i o n was  found  between the length of day-old secondaries to both 10-day t a i l development and to 6- and 8-week back f e a t h e r i n g , i n d i c a t i n g that i t was a l e s s dependable f a c t o r on which to base p r e d i c t ! than was the number of  secondaries.  Results of t h e i r experimental work i n d i c a t e d the presence of "a major autosomal r e c e s s i v e f a c t o r producing 22. Darrow, M.I., and Warren, D.C, "The Influence of Age on Expression of Genes C o n t r o l l i n g Rate of Chick Feathering", P o u l t r y Science. 1944, V o l . 23, pp. 199-212. 23. Loc. c i t .  - 15 -  24 d e f e c t i v e t a i l f e a t h e r i n g at the 10-day age", which they termed "modified e a r l y " . They suggested that t h i s gene was p o s s i b l y the same as "retarded" p r e v i o u s l y found i n White Leghorns, and postulated the presence of a d d i t i o n a l m o d i f i e r s since a l l of the o f f s p r i n g from i n t e r se matings could not be classed as e i t h e r "modified e a r l y " or "retarded". Results of t h e i r work w i t h b i r d s possessing the sexl i n k e d l a t e - f e a t h e r i n g gene i n d i c a t e d the presence of an autosomal dominant modifier of the l a t e - f e a t h e r i n g gene which 25 "somewhat improves primary f e a t h e r i n g " "intermediate".  and which they termed  Chicks possessing t h i s gene are " d i s t i n g u i s h a b l e  from sex-linked e a r l y by possessing lengthened primaries and coverts of about equal length, and by having more slender 2G primaries than are found i n e a r l y stock", the primaries and 27 t h e i r coverts being "of s i m i l a r length of diameter".  This  gene apparently expresses i t s e l f b e t t e r i n males that are heterozygous f o r l a t e f e a t h e r i n g . of the heterogametic  The genetic c o n s t i t u t i o n  female a l s o appeared unfavourable  to the  expression of "intermediate", as there was a shortage of expected females of t h i s type i n t h e i r matings.  From r e s u l t s  presented, i t would not appear that e i t h e r "modified e a r l y " or 24. Darrow, M.I., and Warren, D.C, OJD. o i t . , p. 208. 25. I b i d . , p. 210. 26. I b i d . , p. 209. 27. I b i d . , p. 210.  - 16 "intermediate" could be the "dominant autosomal" gene of Hays and Sanborn which, as s t a t e d above, had a cumulative a c t i o n i n conjunction with the s e x - l i n k e d e a r l y - f e a t h e r i n g gene t o produce complete back f e a t h e r i n g at 8 weeks of age. Jones and Hutt (1946) reported the existence of a m u l t i p l e a l l e l i c s e r i e s of autosomal genes i n White Leghorns, c o n s i s t i n g of the dominant "normal" gene, the secondary dominant "retarded" gene ( p r e v i o u s l y reported by Warren) and the r e c e s s i v e "tardy" gene.  The phenotype of a homozygous "tardy"  chick e x h i b i t e d normal primary but u s u a l l y no secondary f l i g h t development although a few b i r d s were observed which showed 28  "normal development of the f i r s t two or three secondaries." No development of t a i l feathers appeared " u n t i l at l e a s t eight 29  weeics of age and even \ihen tney grow very s l o w l y . "  From the  r e s p e c t i v e d e s c r i p t i o n s given i n t h e i r r e p o r t s , i t would seem that i t was t h i s "tardy" gene with which MoClary and Bearse (1941) had been working f o r , as noted p r e v i o u s l y , the degree of r e t a r d a t i o n of feather development which they reported was more severe than could be a t t r i b u t e d to the a c t i o n of the "retarded" gene. McGibbon and H a l p i n (1946) simultaneously reported the existence of such an a l l e l i c s e r i e s .  However, t h e i r report  did not substantiate the degree of dominance w i t h i n t h i s s e r i e s 28. Jones, D.G., and Hutt, F.B., " M u l t i p l e A l l e l e s A f f e c t i n g Feathering i n the Fowl", Journal of Heredity. 1946, V o l . 37, pp. 109-199. 29. 0p_. c i t . , p. 199.  - 17 that the former i n v e s t i g a t o r s claimed to e x i s t .  Rather,  their  observations i n d i c a t e d that heterozygosity, of "retarded" and "tardy" (or "slow", as they termed i t ) a t l e a s t , gives r i s e to an intermediate expression i n the phenotype.  This report  a l s o mentioned the existence of the "retarded" gene i n t h e i r p a r t i c u l a r s t r a i n of Rhode I s l a n d Reds which acted as an autosomal r e c e s s i v e i n a manner s i m i l a r to i t s expression i n the White Leghorn and i n the six-week-old b i r d was  "expressed  by a narrow median band of f e a t h e r s on the back while the t a i l feathers approximate i n length those of normal e a r l y f e a t h e r ing c h i c k e n s . " ^  0  30. McGibbon, W.H., and H a l p i n , J.G., "Three A l l e l e s A f f e c t i n g Completeness of Feathering i n the Chicken", P o u l t r y Science, 1946, Y o l . 25, p. 406.  - 18 The UBC  S t r a i n of Rhode I s l a n d Reds  (a) H i s t o r y The o r i g i n a l b i r d s of the UBC  RIR f l o c k were imported  i n 1918 from the U n i v e r s i t y of Massachusetts, where s e l e c t i o n f o r e a r l y maturity and high feoundity over the previous s i x years had produced very favourable r e s u l t s i n egg  production.  However, t h i s selected breeding had l e d to such c h a r a c t e r i s t i c s as variegated, l i g h t plumage c o l o r and small s i z e , which were q u i t e mal a propos the standard requirements of the Dominion Government's ROP the UBC  f l o c k was  p o u l t r y breeding program, i n which  entered.  Improvements of c o l o r and type was thus adopted as an immediate o b j e c t i v e .  As s e l e c t i o n along these l i n e s d i d not  produce s a t i s f a c t o r y r e s u l t s i n the f o l l o w i n g three a male, which was outstanding  i n these respects, was  generations, secured  i n 1921 from a w e l l known e x h i b i t i o n s t r a i n i n which mass s e l e c t i o n f o r egg production had been given  considerable  attention. While serving the d e s i r e d o b j e c t i v e , the i n t r o d u c t i o n of t h i s 'blood l i n e ' r e s u l t e d i n d e t e r i o r a t i o n o f f e a t h e r i n g by i n j e c t i n g the now-known dominant slow-feathering  character-  i s t i c i n t o the genetic c o n s t i t u t i o n of the r e s u l t i n g progeny. I t i s to be remembered, however, that such a c h a r a c t e r i s t i c was not one given p a r t i c u l a r s i g n i f i c a n c e by breeders of that day and, equally important,  that the mode of i n h e r i t a n c e of  t h i s f e a t h e r i n g c h a r a c t e r i s t i c was not known at that time. Consequently, f o r almost the next decade, primary c o n s i d e r a t i o n  - 19 was given to improving c o l o r and type, c o n s i s t e n t , of course, w i t h ROP s p e c i f i c a t i o n s regarding egg production. By t h i s time emphasis upon t h i s l a t t e r c h a r a c t e r i s t i c was assuming i n c r e a s i n g importance as the r i s i n g demand f o r eggs focused the breeders' a t t e n t i o n upon the economic value of productive capacity. I n the face of t h i s r i s i n g demand, an e f f o r t t o f u r t h e r s t i m u l a t e egg production i n the UBC s t r a i n was inevitable.  F o l l o w i n g extensive i n q u i r y , two p a r t i c u l a r l y  outstanding s t r a i n s were selected i n 1930 from which to secure breeding males.  Both of these s t r a i n s had been developed  w i t h remarkable success under combined e x h i b i t i o n and bredt o - l a y breeding programs.  The productive c a p a c i t y achieved  from subsequent matings and succeeding generations showed a favourable i n c r e a s e , s e v e r a l females producing over three hundred eggs i n t h e i r p u l l e t year i n the e a r l y 1930's.  In  a d d i t i o n , the i n t r o d u c t i o n of these 'blood l i n e s ' served to increase appreciably the v i g o r and ruggedness of the UBC strain. I n 1935 a program of s e l e c t i o n f o r improvement i n f e a t h e r i n g , growth r a t e and meat type i n the RIR and - f l o c k s was i n s t i t u t e d .  BPR  Such s e l e c t i o n was adapted to conform  as f a r as p o s s i b l e to the growing demand f o r a "quick-growing, 31 e a r l y f e a t h e r i n g , 'streamlined' chicken" by the b r o i l e r 31. L l o y d , E.A., "Breeding f o r Meat and Egg Production", Proc. Seventh World's P o u l t r y Congress and E x p o s i t i o n , Cleveland, Ohio, 1939, p. 484.  - 20 market which, even a t that time, c o n s t i t u t e d "an important 32 33 source of revenue" f o r the west coast p o u l t r y i n d u s t r y . C r i t i c a l observationswere made and f i v e a r b i t r a r y 34 classifications were adopted. S e l e c t i o n of breeding stock 35 from the e a r l y f e a t h e r i n g  c l a s s i f i c a t i o n f a i l e d t o produce  marketable b r o i l e r s by e i g h t weeks of age. At t h i s time, McRae (Milwaukie, Oregon) was successf u l l y o b t a i n i n g completeness of f e a t h e r i n g i n some f a m i l i e s of h i s RIR s t r a i n a t four weeks of age. I n 1937 the Univers i t y imported some baby chicks of t h i s s t r a i n and the f o l l o w ing year an outstanding male was s e l e c t e d from these and mated to females of the UBC s t r a i n .  A l l of the progeny  r e s u l t i n g from t h i s mating were "very e a r l y f e a t h e r i n g a t 32. L l o y d , E.A., op_. c i t . , p. 484. 33. The demand f o r t h i s type of chicken was, a t t h i s time, of a seasonal nature and l a r g e l y confined t o the west ooast areas of Canada and the United S t a t e s . I t arose i n i t i a l l y from the f a c t that weather c o n d i t i o n s i n t h i s r e g i o n favoured e a r l i e r hatching than was p o s s i b l e e l s e where and, consequently, e a r l y production of b r o i l e r s . At t h i s time the s o - c a l l e d Japanese method of c h i c k sexing was j u s t beginning t o make i t s appearance i n America and, c e r t a i n l y , was not being used t o any extent along the west ooast where the White Leghorn predominated throughout the f l o c k s . This f a c t n e c e s s i t a t e d the r e t e n t ion of the male chicks f o r some time i n order t o permit sex determination and p r o f i t a b l e d i s p o s a l was a major concern i n reducing the overhead c o s t s of the i n d u s t r y . Thus, i n s p i t e of the r e l a t i v e l y poor q u a l i t y of such b r o i l e r s , the l o c a l poultrymen were able t o a v a i l themselves of t h i s opportunity t o dispose of t h e i r male c h i c k s at a p r o f i t by concentrating upon e a r l i e r hatching. 34. E a r l y , medium e a r l y , medium, medium l a t e and l a t e f e a t h e r ing. 35. See footnote 15 r e . connotation.  -  21  -  36 s i x weeks of age", i n d i c a t i n g that the UBC s t r a i n was l a c k i n g i n a dominant character f o r r a p i d f e a t h e r i n g i n t h e i r genetic c o n s t i t u t i o n .  During the next few years  intensificat-  i o n of t h i s c h a r a c t e r i s t i c was incorporated i n t o the breeding program.  Unfortunately t h i s was accompanied by an i n c r e a s -  ing s u s c e p t i b i l i t y to fowl p a r a l y s i s .  Decreasing  fertility  and h a t c h a b i l i t y i n some f a m i l y l i n e s a l s o became a major problem. I n an e f f o r t to stem these unfavourable  trends, the  i n t r o d u c t i o n of another 'blood l i n e ' was decided upon.  To  t h i s end a breeding male was secured from a s t r a i n the record of which was very impressive not only i n regard t o these f a c t o r s but, a l s o , i n regard t o egg production, c o l o r , v i g o r and type.  The r e s u l t s obtained were so s a t i s f a c t o r y t h a t t h i s  'blood l i n e ' has since been h i g h l y infused i n the UBC s t r a i n during which period the f l o c k has remained " c l o s e d " .  How-  ever, the enforced concentration upon c h a r a c t e r i s t i c s other than f e a t h e r i n g q u a l i t y has r e s u l t e d i n an appreciable l o s s of e a r l y f u l l n e s s of f e a t h e r i n g which, i n a l a r g e measure, had been secured v i a the McRae s t r a i n .  While continued  sel-  e c t i o n f o r the e a r l y - f e a t h e r i n g s e x - l i n k e d gene has achieved homozygosity of t h i s c h a r a c t e r i s t i c to such a degree that the UBC s t r a i n today i s noteworthy because of i t s extreme t a i l length, the problem of securing r a p i d f u l l n e s s and of e l i m i n a t i n g the unfavourable 3  6  #  "bareback" i s y e t to be solved.  L l o y d , E.A., op_. c i t . , p. 487.  -  (b) Method of Feathering  22  -  Classification  As p r e v i o u s l y noted, f i v e a r b i t r a r y c l a s s i f i c a t i o n s 37 were adopted i n 1935, at eight weeks of age.  based upon the degree of f e a t h e r i n g For the sake of b r e v i t y i n use,  these c l a s s i f i c a t i o n s were soon r e f e r r e d to as Types 1 to 5, s i g n i f y i n g the order of regression of f e a t h e r i n g q u a l i t y . With the i n t r o d u c t i o n of the McRae 'blood l i n e ' and  the  r e s u l t a n t increase i n e a r l y f u l l n e s s of f e a t h e r i n g , recogn i t i o n was  given to such a c h a r a c t e r i s t i c by c l a s s i f y i n g the  b i r d s so feathered as Type FF ( f u l l f e a t h e r i n g ) . Beginning i n 1940,  more a t t e n t i o n was given to the  t a i l development when " t y p i n g " the b i r d s and the s u f f i x e s LT, MT and ST (long, medium and short t a i l ) were adopted as modifiers of the above c l a s s i f i c a t i o n s .  As f a r as p o s s i b l e ,  and with i n c r e a s i n g annual frequency, breeding stock  was  selected from among those b i r d s e x h i b i t i n g long t a i l s at s i x weeks of age.  A l l breeding stock now used i s of t h i s  phenotype, the long t a i l c h a r a c t e r i s t i c being assumed to r e s u l t from the recessive sex-linked e a r l y - f e a t h e r i n g gene 38 i n homozygous form. Such b i r d s are now c l a s s i f i e d as EF 37. See footnote 34. 38. This c l a s s i f i c a t i o n includes a well-represented median d o r s a l feather t r a c t , because the consistency of i t s appearance i n conjunction with a long t a i l would seem to i n d i c a t e that i t could j u s t i f i a b l y be concluded to a r i s e from the possession of the s e x - l i n k e d e a r l y - f e a t h e r i n g gene. The s i m i l a r i t y of t h i s phenotypic d e s c r i p t i o n to t h a t of the "retarded" phenotype reported by McGibbon and H a l p i n i s discussed l a t e r i n t h i s paper.  - 23 (early feathering).  I f a bird  also  e x h i b i t s f u l l n e s s of  f e a t h e r i n g a t t h i s age i t i s c l a s s i f i e d EFFF; i f i t e x h i b i t s a d e f i c i e n c y of f e a t h e r i n g on the back i t i s c l a s s i f i e d EFBB (bareback).  T y p i c a l b i r d s of these c l a s s i f i c a t i o n s , both male  and female, a t s i x and eight weeks of age, are shown i n P l a t e s I I I , IV and V.  I t w i l l be noted t h a t , due to sexual  dimorphism i n the rate of f e a t h e r i n g - which  characteristic  i s quite evident i n the UBC s t r a i n - an EFFF male resembles an EF female and an EF amle resembles an EFBB female.  Thus  extremes i n f e a t h e r i n g a r e , by and l a r g e , represented by an EFFF female and an EFBB male. Comparison of present c l a s s i f i c a t i o n s w i t h photo39 graphs of those o r i g i n a l l y adopted i n 1935  suggest that the  f o l l o w i n g general phenotypic m o d i f i c a t i o n s have evolved: 1955 C l a s s i f i c a t i o n E a r l y (Type 1) or Medium ) E a r l y (Type 2) ) Medium (Type 3) or Medium ) Late (Type 4) ) Late (Type 5) - -  l u s  ±  p i u g  x  *  Present C l a s s i f i c a t i o n _ . Type EFFF t a i l  t a i l  - - - - - -  Medium Late (Type 4 ) - Late (Type 5)  T  w  - plus long t a i l - -  E a r l y (Type 1) or Medium ) i L a r i y u y p e d) ) Medium (Type 3)  _ _  - - —  Type EFBB  (FFMT), 1 (FF or FFST)  T y p e s  - - - - - -  - - - - — - —  —  x  m  Type 1-2  - - -  Type 2  - - - - -  Type 3  For p r a c t i c a l purposes, i t may be stated that a l l b i r d s are now c l a s s i f i e d as e i t h e r EFFF, EF or EFBB. 39.  See footnote 34.  However,  - 24 examination of the accompanying t a b l e s w i l l show that a few b i r d s s t i l l f a i l e d t o f a l l i n t o one of these c l a s s i f i c a t i o n s i n the observations made during the l a s t two years — £6 ( a l l males) out of a t o t a l of 589 i n 1948 and 24 (18 males) out of a t o t a l of 790 i n 1949. I n view of the f a c t that the m a j o r i t y of these b i r d s were progeny of b i r d s known t o be homozygous f o r the e a r l y - f e a t h e r i n g gene, i t would seem that t h e i r appearance r e q u i r e s an explanation other than that they possess the dominant a l l e l e f o r slow f e a t h e r i n g and consequent l a c k of t a i l development. I n the l i g h t of the m u l t i p l e a l l e l i c s e r i e s , known t o e x i s t i n White Leghorns, the above r e s u l t s might be analyzed on the basis of heterozygosity, i n both the dam and the s i r e , f o r the "tardy" gene.  Such would r e s u l t i n 1/4 of the pro-  geny being homozygous "tardy" and, therefore, slow f e a t h e r i n g and t a i l l e s s .  While such a p o s s i b i l i t y cannot be overlooked  as a t l e a s t a p a r t i a l explanation, the w r i t e r i s i n c l i n e d t o the b e l i e f t h a t , i n view of experimental r e s u l t s o u t l i n e d i n t h i s paper, other genetic f a c t o r s are a l s o r e s p o n s i b l e f o r the appearance of such b i r d s i n the U.B.C. f l o c k .  - 25 P r e l i m i n a r y Observations - 1948 As an i n i t i a l step i n the i n v e s t i g a t i o n of the "bareback" problem, observations were made of the f e a t h e r i n g c h a r a c t e r i s t i c s of the RIR c h i c k s hatched i n 1948. A l l males used i n the 1947-48 breeding pens were EFFF.  The eggs were  set biweekly and f i v e hatches were made during March and A p r i l . Unfortunately, f o l l o w i n g the s e l e c t i o n of the breeding stock f o r t h i s season, the f e a t h e r i n g data on the b i r d s hatched i n 1945 was l o s t so that such information was u n a v a i l able f o r t h i s study.  Thus d e f i n i t e c l a s s i f i c a t i o n of nine  females (E56-000 s e r i e s ) could not be s t a t e d .  These females,  together w i t h two others from the 1944 hatch (G-56-000 s e r i e s ) on which f e a t h e r i n g data were l a c k i n g , are noted as "unknown" i n the accompanying t a b l e s , and the tabulated r e s u l t s of the f e a t h e r i n g c h a r a c t e r i s t i c s of t h e i r progeny are recorded separately (see 1948 matings 3a, 3b, 3c, 4a and 4b Tables 4 and 5 ) . Three females, remaining from the 1943-44 hatch (D49-000 s e r i e s ) , were r e t a i n e d f o r p r e l i m i n a r y experimental matings: one Type EFBB, one Type FF(ST) and one Type 2 (see 1948 matings 5, 6 and 7 - Table 6 ) . C l a s s i f i c a t i o n of the progeny of these three females over a three-year p e r i o d (1946-48 i n c l u s i v e ) i s shown i n Table 7. A general observation of the f e a t h e r data suggested that the phenotypic d i f f e r e n t i a t i o n of f e a t h e r i n g c h a r a c t e r i s t i c s of the breeding stock, a t l e a s t i n s o f a r as the EFFF and  - 26 -  EF types were concerned, was of l i t t l e v a l u e i n determining the f e a t h e r i n g c h a r a c t e r i s t i c s of the progeny.  While the  number of EF females used was s m a l l ( t h r e e ) , the data on t h e i r progeny were q u i t e comparable t o those obtained on the progeny of the EFFF females mated t o the same EFFF males. While t h i s would seem t o i n d i c a t e s i m i l a r i t y of g e n e t i c c o n s t i t u t i o n , the f a c t t h a t male H35-507 produced b e t t e r f e a t h e r e d progeny than d i d H35-501 i n the o v e r a l l p i c t u r e and, a l s o , that c e r t a i n females i n d i v i d u a l l y e x h i b i t e d a p p r e c i a b l e v a r i a n c e i n t h e i r progeny, suggest t h a t i n s u f f i c i e n t i a t i o n was b e i n g made i n c l a s s i f y i n g b i r d s EFFF.  different-  Mating 3  a l s o lends weight t o the l a t t e r p o i n t of view and i s perhaps even more i n d i c a t i v e i n t h i s r e g a r d as i t shows the r e s u l t s of the progeny of the same females when mated t o d i f f e r e n t EFFF males.  Thus, w h i l e the p o s s i b i l i t y e x i s t e d t h a t g e n e t i c  d i f f e r e n c e s may be masked and, t h e r e f o r e , not e v i d e n t i n the phenotype, i t was decided t o be more r i g i d i n the c l a s s i f i c a t i o n EFFF the f o l l o w i n g y e a r . Two major o b s e r v a t i o n s were made r e g a r d i n g the experimental females.  F i r s t , although two o f these b i r d s  were p h e n o t y p i e a l l y s l o w - f e a t h e r i n g (see matings 5 and 7 ) , both of them produced e a r l y - f e a t h e r i n g male progeny, as had been noted a l s o d u r i n g the p r e v i o u s two y e a r s . three-year t o t a l s  While the  (see T a b l e 7) a r e not s u f f i c i e n t l y l a r g e t o  be c o n c l u s i v e , i t i s i n t e r e s t i n g t o note t h a t the FF(ST) female produced a l l  e a r l y - f e a t h e r i n g male progeny w h i l e the  - 27 Type £ female produced only one male chick (out of 25) which was not e a r l y - f e a t h e r i n g .  As a l l t h e i r male progeny  would be phenotypically slow-feathering, had these dams been of " t a i l l e s s " c l a s s i f i c a t i o n s because of the  possession  of the dominant l a t e - f e a t h e r i n g gene, i t would appear that they must be g e n o t y p i c a l l y e a r l y - f e a t h e r i n g and that the expression of t h i s character was g e n e t i c a l l y suppressed at the time they were o r i g i n a l l y typed. The second observation was to the e f f e c t that the m a j o r i t y of the male progeny from the EFBB female ( a l l of them i n 1947 and 1948) were t a i l l e s s and that most of these were, i n t u r n , barebacked (Type 2 ) . With the exception of one FE(ST), which might quite p o s s i b l y have been an e r r o r i n view of the number i n v o l v e d (31), n e i t h e r c h a r a c t e r i s t i c appeared i n the female progeny.  The assumption that the  appearance of t a i l l e s s progeny r e s u l t e d from heterozygosity f o r the "tardy" gene i n both s i r e and dam (which would r e s u l t i n 1/4 of the progeny being homozygous "tardy" and, therefore, t a i l l e s s ) can s c a r c e l y be s a i d to d o n s t i t u t e a s a t i s f a c t o r y explanation f o r the high incidence of t a i l l e s s male progeny and the absence (bar one) of t a i l l e s s female progeny.  Evidence  presented seems h i g h l y i n d i c a t i v e that the t a i l l e s s c o n d i t i o n of the (male) progeny i s due t o the barebacked aspect of the dam.  The p o s s i b i l i t y of sex-linkage of t h i s c h a r a c t e r i s t -  i c i s thus suggested.  Table 1. CLASSIFICATION OF TEE FEATHERING- DATA OF THE 1948 FLOCK OF U.B.C. RHODE ISLAND REDS C l a s s i f i c a t i o n of Feathering of Progeny  EFFF  EF  EFBB  1  T o t a l Total Known Unknown  Females  Males  Dam  1-2  2 ( 1)  Total EFFF  EF  EFBB  1  1-2  2  Total  Mating : EFFF d* x EFFF o (a)  o*: H35-501  G56-513  0  6  1  0  0  0  7  3  5  4  0  0  0  12  19  4  G56-525  0  2  8  0  0  0  10  0  3  1  0  0  0  4  14  1  G56-532  0  3  6  0  0  0  9  8  5  9  0  0  0  22  31  8  G56-539  0  2  2  0  0  0  4  10  2  1  0  0  0  13  17  1  G56-545  0  0  5  0  0  0  5  2  4  2  0  0  0  8  13  5  G56-547  1  0  3  0  0  0  4  2  3  1  0  0  0  6  10  0  G56-558  0  6  7  0  0  0  13  6  5  3  0  0  0  14  27  4  G56-578  2  4  1  0  0  0  7  4  8  2  0  0  0  14  21  2  Total  3  23  33  0  0  0  59  | 35  35  23  0  0  0  93  152  25  Note: The following dams shown i n the above mating are f u l l s i s t e r s : G56-532 and G56-545 G56-539 and G56-547  Table 2 . CLASSIFICATION OF THE FEATHERING DATA OF THE 1948 FLOCK OF U.B.C. RHODE ISLAND REDS  C l a s s i f i c a t i o n of Feathering of Progeny Dam  1  Males EFFF  EF  EFBB  1  1-2  2  Females  TotallEFFF  EF  EFBB  1  1-2  2  Total  Total Total Known Unknown  u L) Mating: EFFF cf*x EFFF o. •  (b) o*'. H 3 5 - 5 0 7  G56-516  8  2  2  0  0  0  12  12  1  3  0  0  0  16  28  5  G56-534  3  6  0  0  0  0  9  10  4  0  0  0  0  14  23  4  G56-556  9  4  2  0  0  0  15  18  3  0  0  0  0  21  36  3  G56-576  2  0  0  0  0  0  2  4  0  0  0  0  0  4  6  1  G56-596  2  9  5  0  0  0  16  5  5  5  0  0  0  15  31  7  G56-614  1  1  0  0  0  0  2  2  0  0  0  0  0  2  4  0  G56-636  7  5  2  0  0  0  14  11  1  1  0  0  0  13  27  3  32  27  11  0  0  0  70  62  14  9  0  0  0  85  155  23  Total  |  Note: The f o l l o w i n g dams are f u l l G56-556,  sisters:  G56-576, G56-614 & G56-636 G 5 6 - 5 3 4 and G56-596  Table 5. CLASSIFICATION OF THE FEATHERING DATA OF THE 1948 FLOCK OF U.B.O. RHODE ISLAND REDS  C l a s s i f i c a t i o n of Feathering of ProgenyDam  Males EFFF  EF  EFBB  1  | 1-2  2  ( 2)  Total Total TCnown Unknown  Females  T o t a l EFFF  EFBB  EF  1 toting:  EFFF  (a)  H35-501  1  1-2  2  Total  x EF o.  G56-543  3  6  5  0  0  0  14  3  6  6  0  0  0  15  29  5  G56-558  0  6  7  0  0  0  13  6  5  3  0  0  0  14  27  4  Total  3  12  12  0  0  0  27  9  11  9  0  0  0  29  56  9  0  1  0  0  1  3  3  11  10  0  0  30  59  12  (b) D49-184  1  0  1  0  0  0  Grand Total  4  12  13  0  0  0  H35--507  29  9  0  0  Table 4 (3) Mating: EFFF <f x Unknown ? (b) dS^H35-518 & G30-365  (a) ^ 3 5 - 5 1 8  Dam  Males  r  e EFFF  a E56-038 b o a E56-052 b c a E56-066 b c a E56-074 b c a E56-083 b c a E56-087 b c Total  C l a s s i f i c a t i o n of Feathering of Progeny  S 1  a E56-0S7 b c  a b c  (o) 0*030-365  6~  1 0  z  0 1_ 0 0  c_ 0 0 1_ 0 0 0_  6~  1 2_ 0 0  c_  2 2 4  EFBB 1MT 1-2 ~0~ ~~o~ 0~ 0 ~0~ 0 0 2 0 0 0 0 ~6~ ~~0~ 2, ~ \P 0 0 2 0_ 0 1 0 ~ G 0 2 0 0 0 4 0 0 4 0 0 G 0 1 0 0 0 0 0 2 2__ 0 0 ~~6~ 0 0 0 0 0 o 0 0 o 6~~ ~~b~ 0 o i 0 0 o_ 0 0 0 0 0 0 l 0 l 0 1 0_ 0 0 0 ~"o~ G 6 2 6 0 0 6 0 6 2 2  Females  EF  JL  Total EFFF 0 0 0  T  1 _2_ 0 0  _c_ 0 0 _0_ 0 1 _5_ 0 0 _0_ 0 0 _0_ 0 2 7  0 3  .9  ~6~ 4 4 2 4 4 1 0 5 0 1 6 0 2 2 1 2 0 10 16 21  4 1 0  ~T 3 2 4 1 1 0 0 1 0 2 2  EF ~  0 0 ~0 0 5 3 1 2 1 0 4  1 4 0 1 0  0 0 0 0 0 1 0 0 0  13 9 10  5 1 10  ~Z  EFBB 1MT 1-2 Total ~0~ 0 0 ~G~ 0 ~~5 0 0 0 1 0 0 0 _0_ 0 ~0~ 2 ~ 0 ~ 0 0 3 0 0 0 1 6 _0_ 0 0 2 8 0 0 0 2 0 0 0 0 _0_ 4 1 0 0 0 2 1 0 0 0 0 0 0 0 0 7 2_ 0 0 0 "o" 0 0 0 0 0 2 0 0_ 0 0 2 3 0 ~b~ "o" 1 0 0 0 1 0 0 _0_ 8 3_ 0 0 0 0 0 0 0 0 0 0 1 0 _0_ 0_ 0 0  T  5 0 7  0 0 0  0 0 0  0 0 0  23 10 27  Total Total Known Unknown 5 4 0 11 7 10 10 6 8 3 0 12 0 3 8 3 3 10 1 3 0 33 26 48  ^ - Male J66-833 used f o r experimental breeding 1949-50.  2 0 0  ~~2 0 2 0 0 2 1 0 2 0 1 2  ~~6~ 0 2 1 0 0  6 1 11  Table 5. CLASSIFICATION OF THE FEATHERING DATA OF THE 1948 FLOCK OF U.B.C. RHODE. ISLAND REDS C l a s s i f i c a t i o n of Feathering of Progeny Females  Males  Dam EFFF  EF  EFBB  1-2  1  2  T o t a l EFFF  EF  (4) Mating: EFFF  EFBB  1  x Unknown  1-2  2 Total  Total Total Known Unknown  ?  (a) cr": H35-501 G56-501 G56-555  61  Total  0  2  1  2  1  4  b  5  0  0  0  7  5  7  1  0  0  0  13  20  3  4°  0  1  0  8  11  3  1  0  0  0  15  23  2  9  0  1  0  15  16  10  2  0  0  0  28  43  5  (b) o*i H35-507 d  4  e  2  0  0  0  10  11  3  0  0  0  0  14  24  4  E56-076  0  0  0  1  2  3  9  1  2  0  0  0  12  15  4  Total  4  4  \ °  0  1  2  13  20  4  2  0  0  0  26  39  8  Grand Total  5  8  11  0  2  2  28  36  14  2  0  0  0  82  13  E56-047* i  4  12  a b c d e  -  oo used f o r breeding i n 1949 a l s o . includes J66-836 used f o r breeding includes J37-221 used f o r breeding includes J66-835 used f o r breeding includes J66-811 used f o r breeding  in in in in  54  1949. 1949. 1949. 1949.  Table 6. CLASSIFICATION OF THE FEATHERING- DATA OF THE 1948 FLOCK OF U.B.C. RHODE ISLAND REDS  C l a s s i f i c a t i o n of Feathering of Progeny Males  Dam EFFF  EF  EFBB  1  I 1-2  2  Total(EFFF  Females EF  EFBB  Total Total TTn own Unknown  1-2  2  Total  0  0  3  4  0  0  0  0  6  15  0  0  0  0  7  15  2  1  (5) Mating: EFFF (fx FFST 0, o*H35-507 D49-124  1  0  0  0  0  0  1  I 3  0  0  0  (6) Mating: EFFF cfx EFBB o. D49-154  0  0  0  0  2  7  2  0  (7) Mating: EFFF o^x 2 <j> D49-166  1  4  3  0  0  0  3  1  Table 7 CLASSIFICATION OF THE FEATHERING DATA Off PROGENY OF FOUR FEMALES OVER. A THREE-YEAR PERIOD C l a s s i f i c a t i o n of Feathering of Progeny Dam  Yr.  Males  EFFF »46f 2 D49-124 »47 (FFST) •48 1 d  EF 4 2  EFBB  1  | 1-2  2  '46 J D49-154 •47 (EFBB) »48  3  '46$ D49-166 »47 (Type 2] '48®  2*  d  3  d  1  '46° 10J D49-184 •47 2 (EF) '48 d  8 2 4  4 3  4  f  EF 3 7  16 1 3  23 8 9  11 9 4  5 12 2  1  14 3 8  11 5 3  4 4 3  1  10 7 0  12 3  3 6  2 3  e  Total|EFFF  6 2 1  e  2 2  13 5 7  Total Total Known Unkn.  Females EFBB  1 1 3  1-2  2  Total 20 11 3  26 13 4  0  16 22 6  39 30 15  10 3 0  15 9 7  29 12 15  3l 2  1  16 9 0  26 16 0  7i 0 0  1  1  4  Three-year Totals by Dam D49-124  3  6  D49-154  3  3  D49-166  3  14  D49-184  12  4  20  10  4  34  43  12  40 : 24  19  1  44  84  13  31  56  18  25  42  7  9 5 7  4  25  1  25  20  11  1  17  15  9  1 1  See following page regarding subscripts.  Table 7 (Cont'd) - Subscripts a - Sire E39-266. Feathering type unknown (lost data), b - Sire E39-708. Feathering type unknown (lost data), c - Sire E39-195. Feathering type unknown ( l o s t data), d - S i r e G30-330. Feathering type EFFF. e - S i r e H35-507. Feathering type EFFF. f - Not used f o r breeding i n 1948. i  g - Including Male G56-555 used f o r breeding i n 1948 & 1949. h - Including Male G30-333 used f o r breeding i n 1947. i - Including Male G30-331 used f o r breeding i n 1947. -j - Including Males G30-355 & G30-357 used f o r breeding i n 1947. k - Two Type 1 and one Type EF.birds included. 1 - Type EF birds but sex unknown i n a l l cases.  w '  Table 8. SUMMARY OF 1948 PROGENY TOTALS RESULTING FROM VARIOUS MATINGS C l a s s i f i c a t i o n of Feathering of ProgenyMating Number  Males EFFF  EF  Females  EFBB 1MT 1-2  2 T o t a l EFFF  EF  EFBB 1MT 1-2  2 Total  Total Total Known Unknown  #la  3  23  33  0  0  0  59  35  35  23  0  0  0  93  152  25  # lb  32  27  11  0  0  0  70  62  14  9  0  0  0  85  155  23  # 2a  3  12  12  0  0  0  27  9  11  9  0  0  0  29  56  9  #2b  1  0  1  0  0  0  2  0  0  1  0  0  0  1  3  3  § 3a  2  0  6  2  0  0  10  13  5  5  0  0  0  23  33  6  # 3b  2  6  6  0  0  0  16  9  1  0  0  0  0  10  26  1  # 3c  4  2  6  0  2  7  21  10  10  7  0  0  0  27  48  11  # 4a  11  4  9  0  1  0  15  16  10  2  0  0  0  28  43  5  # 4b  4  4  2  0  1  2  13  20  4  2  0  0  0  26  39  8  # 5  1  0  0  0  0  0  1  3  0  0  0  0  0  3  4  0  # 6  0  0  0  0  2  7  9  4  2  0  0  0  0  6  15  0  # 7  1  4  3  0  0  0  8  3  3  1  0  0  0  7  15  2  Totals  54  82  89  2  6  18  95  59  0  0  0  338  589  93  251 [ l 8 4  For p a r e n t a l f e a t h e r i n g types see f o l l o w i n g page.  0*1135-501 X 8 EFFF.  #3C  O*H35-507 x 7 EFFF  - 0*030-•365  X  7 Unknown £<j>  #4a - 0*^35-•501  X  2 Unknown £<j>  0*1135-501 x 2 EF <j>c-  #4b - o*H35-•507  X  2 Unknown oo  0^135-507 x 1 EF c_  #5  - o*H35-•507  X  1 Type 1 £  0^35-518 x 7 Unknown ^<j>  #6  - c/H35-•507  X  1 EFBB o  00^35-518 & G30-365 x 7 Unknown o^  #7  - 0*1135-•507  X  1 Type 2 £  Note: The 09 i n Matings 3a, 3b and 3c are the same. 0*1135-518 died during the regular breeding season and was replaced by o G-30-365. Hence the p a t e r n a l parentage of the progeny shown i n Mating 3b i s u n c e r t a i n as these c h i c k s were hatched from eggs l a i d during the time i n t e r v a l required to be observed f o r d e f i n i t e sperm replacement under ROP r e g u l a t i o n s . All  noted above are EFFF.  - 38 Observations - 1949 A l l three phenotypes were represented i n the males used during the 1949 breeding season - one EFFF, two EF and  one  EFBB - which afforded the opportunity of observing the e r i e c t of a male's f e a t h e r i n g c h a r a c t e r i s t i c s on tnose or n i s progeny. As i n the previous year, f i v e biweekly hatches were made, the f i r s t o c c u r r i n g February 28th and the l a s t A p r i l 25th. The decrease i n the number of b i r d s c l a s s i f i e d EFFF t h i s year was, of course, a d i r e c t r e s u l t of more r i g i d s e l e c t i o n decided upon f o l l o w i n g a n a l y s i s of the 1948 data. An i n t e r e s t i n g p o i n t , though perhaps of l i t t l e consequence, was t h a t , i n s p i t e of using a l l three phenotypes i n the s i r e s , the percentages of male and female progeny c l a s s i f i e d EFFF c l o s e l y r e t a i n e d the same r e l a t i v e p r o p o r t i o n as the previous year, roughly a 1:3  ratio: Males  Females  1948 -  21.5% (54/251)  54.4% (184/338)  1949 -  12.8% (46/359)  36.9% (159/431)  A very n o t i c e a b l e f e a t u r e of t h i s year's data was  the  absence of EFFF male progeny, and the very l i m i t e d number of EFFF female progeny (20%), r e s u l t i n g from the mating of the EFFF male to three EFFF females.  This i s p a r t i c u l a r l y s t r i k i n g  i n view of the EFFF progeny obtained from the other three males when mated to females of t h i s c l a s s i f i c a t i o n , both EF males producing approximately 20% males and 40% females while the EFBB male produced 8% and 36% r e s p e c t i v e l y .  As the EFFF  -39male, when mated to three EF females, produced approximately 1/3 EFFF progeny, both male and female, r e s u l t s d i d not cons i s t e n t l y s u b s t a n t i a t e the assumption of i n s u f f i c i e n t d i f f e r e n t i a t i o n i n the EFFF category, although such a hypothesisoould e x p l a i n the r e s u l t s of i n d i v i d u a l cases i n a s a t i s f a c t o r y manner. A decided decrease i n the number of b i r d s c l a s s i f i e d EFBB a l s o was observed.  To a l a r g e degree, t h i s could pro-  bably be explained as a r e s u l t of continued s e l e c t i o n f o r b e t t e r f e a t h e r i n g q u a l i t y i n the past p l u s a probable fortunate choice of breeding stock.  The increased a t t e n t i o n  paid to the appearance of t h i s type i s probably r e f l e c t e d here a l s o .  While the percentage of male and female b i r d s of  t h i s type i n the 1948 hatch was i n the r a t i o of 2:1, the number of females secured i n the 1949 hatch was not suff i c i e n t l y large to be i n d i c a t i v e i n t h i s regard: Males 1948  -  35.3% (89/251)  1949  -  3 i 9 % (14/359)  Females 17.5% (59/338) 0.9% (4/431)  The observation of most i n t e r e s t , however, was that the EFBB male produced both t a i l e d and t a i l l e s s progeny when mated to EFFF females (see 1949 mating 6 ) . While i t i s to be admitted t h a t both p a r t i a l l y b a i l l e s s (Type 1MT)  and  completely t a i l l e s s (Types 1-2 and 2) progeny were not secured from any one i n d i v i d u a l female, the o v e r a l l r e s u l t of t h i s mating i s s i m i l a r to t h a t obtained i n the progeny of the EFBB female (Experimental,,1948) over a three-year  - 40 period (see Table 7) except t h a t , i n t h i s l a t t e r instance, these types appeared only i n the male progeny.  (Although  both of these types were not produced by t h i s female i n  1948,  reference to Table 7 w i l l show that they were produced i n each of the preceding two years.  This f a c t favours  the  assumption that the same r e s u l t s could have been expected from the EFBB male had the numbers of h i s progeny been s u f f i c i e n t l y l a r g e ) . Aside from t h i s , however, t h i s observa t i o n served as an a d d i t i o n a l i n d i c a t i o n that the bareback c h a r a c t e r i s t i c of the breeding stock gave r i s e to t a i l l e s s ness i n the progeny and, too, that p o s s i b l y there was  sex-  linkage of the f a c t o r ( s ) i n v o l v e d . The f a c t that one of the EF males used (J66-836) a l s o produced t a i l l e s s progeny (male only i n the EFFF and matings; both male and female i n the EF mating - see  FF  1949  matings 3b, 4b and 5) can probably be explained on the grounds that t h i s b i r d had been i n c o r r e c t l y c l a s s i f i e d at s i x weeks of age and was,  i n r e a l i t y , Type EFBB.  e r r o r could quite p o s s i b l y a r i s e from two sources.  Such an First,  i t should be remembered that the three phenotypic c l a s s i f i c a t i o n s used are purely a r b i t r a r y and t h a t , while the majority of the b i r d s are r e l a t i v e l y easy to type according to these c a t e g o r i e s , there are, nevertheless,  several  i n d i v i d u a l s which c o n s t i t u t e " b o r d e r l i n e " cases and which, therefore, may  be i n c o r r e c t l y c l a s s i f i e d .  I n t h i s regard,  environmental, n u t r i t i o n a l and other non-heritable f a c t o r s which a f f e c t f e a t h e r i n g q u a l i t y may a l s o lead to improper  -  classification.  41  -  I t should he noted here, too, that lateness  i n season a l s o has been observed t o m i l i t a t e against both the rate of f e a t h e r i n g and r a t e of growth v i a a higher  incidence  of p a r a s i t i c i n f e s t a t i o n which, i n t u r n , i s due to the f a c t that, as the season advances, weather conditions become more favourable t o p a r a s i t i c development.  Where confinement  r e a r i n g i s not p r a c t i s e d , such as i s the case at the U n i v e r s i t y , i n f e s t a t i o n of t h i s type can become q u i t e detrimental.  A  second reason, of equal or p o s s i b l y more importance, i s the f a c t that the exact mode of i n h e r i t a n c e involved i n the case of the "bareback" i s not known and t h a t , t h e r e f o r e , i t i s not impossible f o r the responsible gene (s) to be masked i n the phenotype.  Indeed i t would seem that only by way of such a  p o s s i b i l i t y could the appearance of bareback progeny from non-bareback stock be explained.  Table 9. CLASSIFICATION OF THE FEATHERING DATA OF THE 1949 FLOCK OF  RHODE ISLAND REDS  U . B . C .  C l a s s i f i c a t i o n of Feathering of ProgenyDam  Males EFFF  EF  EFBB|  1MT  Females 1-2  2  T o t a l EFFF  EF  EFBB IMT 1-2  (1) Mating: EFFF c^x EFFF  2  Total  Total Total Known Unknown  -  T  d*": J66-•835 H57-365  0  7  0  0  0  0  7  0  4  0  0  0  0  4  11  1  H57-416  0  4  0  0  1  0.  5  2  2  0  0  0  0  4  9  7  G56-534  0  13  0  0  0  0  13  1  6  0  0  0  0  7  20  7  Total  0  E4  0  0  1  0  25  3  12  0  0  0  0  15  40  15  (2) Mating : EFFF o^x EF <j> <Z:  J66--835  H57-399  1  1  1  0  0  0  3  3  3  1  0  0  0  4  7  0  H57-457  0  6  1  0  0  0  7  0  7  0  0  0  0  7  14  1  H57-470  5  6  0  0  0  0  11  4  5  0  0  0  0  9  -20  2  Total  6  13  2  0  0  0  21  7  13  0  0  0  0  20  41  3  Table 10. CLASSIFICATION OF THE FEATHERING DATA OF THE 1949 FLOCK OF U.B.C. RHODE ISLAND REDS C l a s s i f i c a t i o n of Feathering of ProgenyMales  Dam EFFF  EF  F«jmales  EFBB 1MT 1-2  2 T o t a l EFFF (3)  EF |EFBB 1MT 1-2  2 Total  Total Total Known Unknown  Mating: EF cfx EFFF o (a) cf: J66-811  H57-306  0  2  1  0  0  0  3  4  5  0  0  0  0  9  12  6  H57-372  2  8  1  0  0  0  11  5  14  2  0  0  0  21  32  6  H57-379  1  4  0  0  0  0  5  1  1  0  0  0  0  2  7  3  H57-398  5  13  0  0  0  0  18  5  9  0  0  0  0  14  31  5  H57-417  2  1  0  0  0  0  3  6  0  0  0  0  0  6  9  1  H57-461  0  12  1  0  0  0  13  5  5  1  0  0  0  11  24  0  H57-465  1  9  0  0  0  0  10  6  6  0  0  0  0  12  22  4  Total  11  49  3  0  0  0  63 [ 31  40  3  0  0  0  75  138  25  0 0 0 0 0  0 0 0 0 0j  0 0 0 0 0  0 0 0 0 0  2 6 12 13 33  8 10 26 28 72  2 0 4 9 15  (b) cf: J66-836 H57-335 H57-359 H57-391 H57-444 Total  2 1 4 1 8  4 3 e 12 27 r  0 0 1 0 1  0 0 0 0 0  0 0 1* 1 2  0 0 0 1 1  6 | 2 4 3 14 3 3 15 39 11  I  # T?urrfc.  0 3 9 10 22  Table 11. Dam EFFF  IF  C l a s s i f i c a t i o n of Feathering of ProgenyMales Females EFBB 1MT 1-21 2 T o t a l EFFFi EF EFBB 1MT 1-2  2  Total  Total Total Known Unknown  (4) Mating: EF 0* x EF 9 (fa) 0*: J66-811 H57-384  0  6  0  0  0  0  e|  1  0  0  0  0  9  15  11  10 9 5 13 4 41  0 0 0 0 0 0  0 0 0 0 0 0  0 1 0 1 0 2  0 0 0 0 0 0  18 12 6 17 9 62  37 22 9 29 20 117  2 1 3 1 4 11  49  0  0  2  0  71  132  22  0  0  0  8  22  10  8  (b) </: J66-836 H57-309 H57-358 H57-436 H57-472 H5 7-481 Total  1 0 0 1 0 2  17 8 3 10 11 49  1 0 0 1 0 2  0 0 0 0 0 0  0 1 0 0 0 1  0 1 0 0 0 1  19 10 3 12 11 55 ||  Grand Total  2  55  2  0  1  1  61  8 2 1 3 5 19 20  (5) Mating: EF d*x FF o. 0": J66-836 H57-402  0  12  0  0  2  0  14 |  3  5  0  Table 12. C l a s s i f i c a t i o n of Feathering of Progeny Females Males  Dam EFFF  EF  EFBB 1MT 1-2  2 1Total  EFFFI  EF  Total Total Known Unknown  2  Total  0 0 1 0 0 0 0 0 1 0 2  0 0 0 0 0 0 0 0 0  22 13 11 10 15 15 4 20 9  32 15 14 22 28 23 5 24 19  15 10 7 6 6 13 0 8 3  0 0  14 133  24 206  2 70  0 0 0 0 0  0 0 0 0 0  9 17 12 9 47  21 30 22 12 85  6 3 5 8 22  IEFBBIBHTII-2  (6) Mating: EFBB cf x EFFF o. cf : J37-221 H57-302 H57-332 H57-422 H57-423 H57-427 H5 7-438 H57-451 H57-458 H57-467 H57-705 Total  3 0 0 1 0 0 0 0 1 1 6  6 2 2 9 12 7 1 4 7  1 0 0 1 1 0 0 0 0  0 0 1* l 0 1 0 0 0  8 58  1 4  0 3  a  B  0 0 0 0 0 0 0 0 2 0 2  0 0 0 0 0 0 0 0 0  10 2 3 12 13 "8 1 4 10  12 2 3 2 3 6 3 6 0  10 11 7 7 12 8 1 14 8  •o  0 0 0 0 1 0 0 0  0 0 10 2 11 0 80 1 73 48 a.. Medium T a i l . b. Runt.  1  0 0 0 1 0 0 0 0 0 l 2  a  <7) Mating: EFBB cf x EF o cf : J37-221 H57-325 H57-328 H57-368 H57-447 Total  3 2 1 3 9  9 10 8 0 27  0 1 1 0 2  0 0 0 0 0  0 0 0 0 0  0 0 0 0 0  7 12 8 13 10 4 4 3 38 | 23  2 9 8 5 24  0 0 0 0 0  0 0 0 0 0  Table 13. CLASSIFICATION OF THE FEATHERING DATA OF THE 1949 FLOCK OF U.B.C. RHODE ISLAND REDS C l a s s i f ioation of Feathering of ProgenyDam  Females  Males EFFF  EF  EFBB 1MT 1-2  2  Total EFFF  EF  EFBB 1MT 1-2  1,8) Mating: EFFF o*x Unknown  2  Total  Total Total Known Unknown  ^  </: J66-835 H57-349  1  4  0  0  0  0  5  1  2  0  0  0  0  3  8  3  G56-555  0  11  0  0  1  0  15  10  5  0  0  0  0  15  30  7  E56-038  0  0  0  0  2  1  3  2  8  0  0  0  0  10  13  2  E56-047  0  1  0  0  0  1  2  0  1  0  0  0  0  1  3  7  Total  4  16  0  0  3  2  25  16  0  0  0  0  29  54  19  J  13  Table 14, SUMMARY OF 1949 PROGENY TOTALS RESULTING FROM VARIOUS MATINGS C l a s s i f i c a t i o n of Feathering of Progeny Mating Number  Males EFFF  EF  Females  EFBB 1MT 1-2  2  Total EFFF  EF  EFBB 1MT 1-2  2  Total T o t a l Unimown Tot. Known  # 1  0  24  0  0  1  0  25  3 " 12  b  0  0  0  15  40  15  # 2  6  13  2  0  0  0  21  7  13  0  0  0  0  20  41  3  # 3a  11  49  3  0  0  0  63  32  40  3  0  0  0  75  138  25  # 3b  8  27  1  0  2  1  39  11  22  0  0  0  0  33  72  15  #4a  0  6  0  0  0  0  6  1  8  0  0  0  0  9  15  11  # 4b  2  55  2  0  1  1  61  20  49  0  0  2  0  71  132  22  # 5  0  12  0  0  2  0  14  3  5  0  0  0  0  8  22  10  # 6  6  58  4  3  2  0  73  48  80  1  2  2  0  133  206  70  # 7  9  27  2  0  0  0  38  23  24  0  0  0  0  47  85  22  # 8  4  16  0  0  3  2  25  13  16  0  0  0  0  29  54  19  46  281  14  3  11  4  359  159  261  4  2  4  0  431  790 .  201  Totals  For parental feathering types see following page.  Table 14 (Cont'd.) #1 - EFFF (J66-835) #2 - EFFF (J66-835) #3a - EF (J66-811) (J66-836) #3° - EF #4a - EF (J66-811) #4b - EF (J66-836) (J66-836) #5 - EF #6 - EFBB (J37-221) #7 - EFBB (J37-221)  X  #8  - EFFF (J66-835)  X  3 EFFF Females n 3 EF  X  7 EFFF  tt  X  tt  X  4 EFFF 1 EF 5 EF 1 FF 10 EFFF 4 EF  X  4 Unknown  tt  X X X X  tt it tt tt tt  An Accounting of the "Unknowns" of the 1949  Flock  1. E a r l y M o r t a l i t y - This group includes a l l birds known d e f i n i t e l y to have died prior to the recording of data regarding sex and feathering c l a s s i f i c a t i o n . 2. No Record - This group includes a l l birds on which no data were obtained other than the f a c t that they were wing-banded. Birds whose l o s t wing bands were not retrieved are included as i s also mortality due to preying animals and b i r d s . In t h i s group, too, are birds which wander astray from t h e i r respective houses and excajpe detection u n t i l such time as they are useless f o r recording desired data.  Number 93  77  3. Lost Wing-bands - Includes those birds whose l o s t wing-bands are retrieved f o r i d e n t i f i c a t i o n . 4. Sex Only Noted  - Due to oversight at the time no feathering data was noted at the time of observation  5. Sex Not Noted - - In some cases sex i d e n t i f i c a t i o n at the time of gathering the data was too indecisive to be considered r e l i a b l e . Total  18 201  - 49 Experimental Matings and Observations - 1949 and  1950  1. Reoiprooal Matings of the Regular 1949 RIR Breeding Pens I n order to i n v e s t i g a t e the extent of p o s s i b l e e r r o r a r i s i n g from i n c o r r e c t c l a s s i f i c a t i o n a t s i x weeks of age  and,  a l s o , to i n v e s t i g a t e more thoroughly the e f f e c t of the male's f e a t h e r i n g c h a r a c t e r i s t i c s upon those of h i s progeny, i t was decided to interchange the males of the 1949 breeding pens, to continue such breeding f o r a three-week period  (allowing  the l a s t two weeks i n which to c o l l e c t hatching eggs) and to adopt a method of c l a s s i f i c a t i o n ( a d d i t i o n a l to that normally used at s i x weeks) which would give greater r e c o g n i t i o n to v a r i a b i l i t y i n the r a t e of back f e a t h e r i n g . For comparative purposes, the EFFF and EFBB males were interchanged as were a l s o the two EF males, one of which could now be assumed to be a p o s s i b l e EFBB b i r d .  The progeny  of these matings were hatched on J u l y 25th and 26th, an i n cubation period of 22 days being allowed i n order to secure as l a r g e a hatch as p o s s i b l e .  I t i s i n t e r e s t i n g to note that  a l l seven of the a d d i t i o n a l chicks secured i n t h i s manner showed good v i a b i l i t y as they a l l survived the f u l l 12-week period p r i o r to the hatch being marketed.  The sex r a t i o was  normal (four males, three females) as was a l s o the v a r i a t i o n i n f e a t h e r i n g c h a r a c t e r i s t i c s e x h i b i t e d when compared with the remainder of the hatch (males: one EFMS, two EFNS, one EFNSBB; females: one EFFF, one EFMS, one EFNS —  see ex-  planation of c l a s s i f i c a t i o n s here employed l a t e r on).  They  d i d , however, show a s l i g h t tendency towards lower weights a t  - 50 eight weeks of age (males: 1.26  l b s . ; females: 1.11  lbs.).  As a l l a v a i l a b l e f a c i l i t i e s f o r f l o o r brooding were already i n use w i t h the regular season's hatch, these chicks were reared i n confinement.  M u l t i - t i e r e l e c t r i c brooders  were used f o r the f i r s t four weeks, holding cages f o r the second four weeks, while f l o o r r e a r i n g was used f o r the f i n a l four-week period p r i o r to marketing.  While such a  method unfortunately involved a change of environmental f a c t o r s and t h e i r consequent e f f e c t on the r a t e of f e a t h e r i n g , i t , nevertheless,  allowed observations  of feather development  under conditions which c l o s e l y simulated those normally encountered i n the commercial b r o i l e r i n d u s t r y . An attempt was made to o l a s s i f y these b i r d s i n the l i g h t of the m u l t i p l e a l l e l i c s e r i e s found to e x i s t i n White 40 Leghorns.  Observations c a r r i e d out at the 1-day, 10-day  and 3-week periods d i d not i n d i c a t e the presence of t h i s s e r i e s of genes i n the U n i v e r s i t y s t r a i n of Rhode I s l a n d Reds. The range i n development of secondary f l i g h t feathers  and  t a i l s encountered i n t h i s hatch i s shown i n P l a t e I .  These  three b i r d s are the male members of a t y p i c a l f a m i l y (3 males, 4 females) which i s shown i n P l a t e I I at four, s i x and weeks of age.  eight  (The f a c t that a l l three b i r d s selected f o r  photographing at ten days of age were males i s purely c o i n c i d e n t a l . ) While the b i r d s shown i n P l a t e s l b and I c may 40. Phenotypic d e s c r i p t i o n s as noted by Jones and Hutt were used f o r guiding purposes i n t h i s i n v e s t i g a t i o n . See Jones and Hutt, M u l t i p l e A l l e l e s , pp. 197-199.  - 51 be s a i d t o approach the phenotype of a "retarded" Leghorn,  41  i n s o f a r as secondary f l i g h t feather development i s concerned, the degree of r e t a r d a t i o n shown ( i n the Rhode I s l a n d Red) i s of such l i t t l e consequence i n contrast t o that e x h i b i t e d by a "retarded" Leghorn t h a t i t could not be considered nificant. clusion.  sig-  Two other considerations substantiate t h i s conF i r s t , while not t o the same degree as shown i n  P l a t e I a , both of these b i r d s e x h i b i t e d f a i r t a i l development at t h i s age. This f a c t i s not too noticeable i n the photographs mainly because the t a i l feathers had not unsheathed at t h i s age but were, r a t h e r , i n the p i n stage of development. Thus, i n s p i t e of having a t t a i n e d an appreciable l e n g t h , they are not i n c l i n e d to show too d i s t i n c t l y i n the photographs. A "retarded" Leghorn chick at t h i s age has "no s i g n of a t a i l " according to Jones and Hutt, which f a c t would not i n d i c a t e that these b i r d s are of the retarded phenotype.  Second, i t  must be remembered that Rhode I s l a n d Reds do not feather out as r a p i d l y and f u l l y as do White Leghorns i n the same length of time.  No chick i n t h i s hatch showed feather development  equal t o t h a t of a normal-feathering  Leghorn although a few  such as the male shown i n P l a t e I a , approached t h i s degree. On the other hand, a l l of the chicks e x h i b i t e d development superior t o that of a "retarded" Leghorn.  On the assumption  that a "retarded" Rhode I s l a n d Red chick would show even l e s s 41. Jones and Hutt, op_. c i t . , F i g . 23, p. 198. 42. I b i d . , p. 199.  -  52  -  development than a "retarded" Leghorn does a t t h i s age,  such  would seem to i n d i c a t e that a l l of the chioks of t h i s hatch were "normal" i n s o f a r as t h i s terminology i s used r e l a t i v e to the m u l t i p l e a l l e l i c s e r i e s . The above, however, i s not t o be i n t e r p r e t e d as precluding v a r i a t i o n i n the f e a t h e r i n g q u a l i t y throughout the hatch.  Rather, i t i s o f f e r e d as evidence that f a c t o r s  other than those of the a l l e l i c s e r i e s are responsible f o r the gradations  i n f u l l n e s s of f e a t h e r i n g noted a t l a t e r  stages of development.  A c t u a l l y , as noted by Darrow (1941),  v a r i a t i o n s i n t a i l development were found t o serve as e x c e l l e n t c r i t e r i a f o r p r e d i c t i o n of f u l l n e s s of f e a t h e r i n g of the back a t eight weeks of age.  A t t h i s time, the males  shown i n P l a t e l a , l b and I c were c l a s s i f i e d EFWS, EFNS and EFNSBB r e s p e c t i v e l y , thus covering tne extremes i n f u l l n e s s of f e a t h e r i n g noted i n a p a r a l l e l manner t o which extremes i n t a i l development were observed a t ten days of age. l i e , showing these b i r d s a t eight weeks of age,  Plate  illustrates  t h i s pointvery w e l l . A major observation was that a l l of the progeny from these four matings were e a r l y - f e a t h e r i n g . previous r e s u l t s obtained,  I n the l i g h t of  i t would appear that t h i s f a c t can  only be i n t e r p r e t e d as c o i n c i d e n t a l .  Such a s i t u a t i o n , how-  ever, could not serve as a basis upon whioh t o formulate any hypotheses r e l a t i v e t o the i n h e r i t a n c e o f the bareback characteristic. A f u r t h e r observation was made t o the e f f e c t that  -  53  -  there was no d e f i c i e n c y of male progeny, such as was i n both the 1948 and 1949  data.  noted  A l l of the c h i c k s which  died before sex could be determined v i s u a l l y w i t h c e r t a i n t y were "posted" to insure accuracy  i n t h i s regard.  of such evidence i t would seem t h a t much of the  I n the face discrepancy  p r e v i o u s l y observed was due to i n c o r r e c t c l a s s i f i c a t i o n at the time t h i s information was gathered.  As the tendency of  such e r r o r s would admittedly be i n t h i s d i r e c t i o n , p o s s i b i l i t y presented  this  i t s e l f as a r a t h e r d i s t u r b i n g feature  i n view of the importance placed upon sex i n the a n a l y s i s of the data of the preceding two  years.  As p r e v i o u s l y noted, the chicks were c l a s s i f i e d i n the usual manner at s i x weeks of age on the b a s i s of three phenotypes.  At eight weeks of age they were r e - c l a s s i f i e d  i n t o f i v e groups, based upon the extent of the back f e a t h e r i n g as noted below: (EF)FF (EF)WS (EF)MS (EF)NS (EFNS)BB  -  F u l l y feathered back Wide median d o r s a l streak Medium width median d o r s a l streak Narrow unbroken median d o r s a l streak Narrow broken median d o r s a l streak or bare back.  I t i s to be noted that the bracketed p o r t i o n s of these c l a s s i f i c a t i o n s do not appear i n Table 9 showing the r e s u l t s of these two methods of c l a s s i f i c a t i o n . omitted s o l e l y f o r the purpose of enabling a presentation of the data.  These were  single-page  Reference to t h i s t a b l e w i l l show  the r e l a t i v e inadequacy of the normal manner of c l a s s i f y i n g the b i r d s i n t o three categories at s i x weeks of age, as shown  - 54 by the extensive i n t e r n a l v a r i a t i o n i n each of these categories a t e i g h t weeks of age. This evidence probably explains much of the d i f f i c u l t y p r e v i o u s l y encountered i n attempting  t o secure d i f f e r e n t i a t i o n i n c l a s s i f i c a t i o n of the  progeny on the b a s i s of the f e a t h e r i n g c h a r a c t e r i s t i c s of the parental stock.  The r e s u l t s , a l s o , would seem to i n d i c a t e the  f e a s i b i l i t y of c l a s s i f y i n g f e a t h e r i n g c h a r a c t e r i s t i c s at eight weeks of age r a t h e r than a t s i x weeks although c o n s i d e r a t i o n must be given here to the f a c t that c l a s s i f i c a t i o n on the b a s i s of f i v e types rather than three was not used at t h i s l a t t e r age. I n view of the p a r a l l e l i s m noted between e i g h t week feather development and 10-day t a i l development i t would seem such a system of c l a s s i f i c a t i o n could be used at s i x weeks with equal success.  However, as the data presented i n  Table 9 would appear t o i n d i c a t e a lack of u n i f o r m i t y of feather development between s i x and eight weeks throughout the e n t i r e hatch, the l a t e r age may be s a i d to be p r e f e r a b l e . Data on the r e s u l t s of the four matings are presented i n Table 10, being grouped together according t o s i r e and f e a t h e r i n g c l a s s i f i c a t i o n a t eight weeks of age a t which time 148 of the 163 chicks o r i g i n a l l y hatched s t i l l  survived.  Both the combined and average weights of the i n d i v i d u a l s w i t h i n each group are a l s o shown.  These data were secured i n  an attempt t o c o r r e l a t e eight-week feather development with e i g h t week body growth, the existence of which i s a debatable point i n view of c o n f l i c t i n g conclusions r e s u l t i n g from i n v e s t i g a t i o n in this f i e l d .  I t w i l l be noted t h a t , w i t h i n each f a m i l y ,  - 55 Tafrle 15. C l a s s i f i c a t i o n C l a s s i f i c a t i o n of Feathering at 8 Weeks of Males Mating ""feathering Females at 6 Male Female Weeks FF ws MS NS BB Total FF WS MS NS BB Total EFFF EFFF EF(a) EF(a) EF(a) EF(b) EF(b) EFBB EFBB EFBB  X x x x x x x x x x  EFFF EF EFFF EF FF EFFF EF EFFF EF Unkn  2 EFFF  1  Group T o t a l EFFF EFFF EF(a) EF(a) EF(h) EF(b) EFBB EFBB  x x x x x x x  ^x^^  j Broup T o t a l  EFFF EFFF EF(a) EF(a) EF(a) EF(b) EF(b) EFBB EFBB EFBB  x EFFF x EF x EFFF x EF x FF x EFFF x EF x EFFF x EF ac Unkn  X  0 0 2 0 0 0 0 0 0 1  EFFF EF EFFF EF EFFF EF EFFF EF  0  3  0  0  2  1  1  1  1  EF  GRAND TOTALS  1°  |  1 1 2  3  2  2 2 4 2  3  11 13  4  4 0 0 2 3 0 1 1  3 1  1  1 1  4 1 1  1 1  0  0  1  2  11 0 1 1 2 2 0 2 7 2  11 0 3 1 2 2 0 2 7 3  28  31  4 1 1 2 6 1 2 1  8 1 1 4 9 1 3 2  3  2  4  11  2 10  5  1  0  18  29  3  7 4  4  5 2  2  2  2  3  1  2  19 6 1 3 1 7 1 10 6 9  2 1 1  1  9 0 2 2 0 5 2 4 0 1  28 6 3 5 1 12 3 14 6 10  1 3 0  5  2  1 1  EFBB  Group Total  3 1  1 0  0  4  2 4 4  1 2  8 23  7 1 8  9 23  63  13 26 12 27  77  1 1 1 .1 3 1 2  1 0  4 10  7  4  25  88  13 27 19  8  4  71  148  Note: A l l LOf the progeny of the above matings were early-feathering. EFFF Male EF(a) Male EF(b) Male EFBB Male  J66-835 J66-811 J66-836 J37-221  FF WS MS NS BB  -  F u l l y feathered back Wide median dorsal streak Medium median dorsal streak Narrow median dorsal streak Bare back  Table 16 WEIGHT OF RHODE ISLAND REDS AT EIGHT WEEKS OF AGE CLASSIFIED ACCORDING TO FEATHERING GROUP  Feathering : Groups of Progeny EFFF  No. Birds T o t a l Wt. Average  S i r e ' s Number and Feathering Type J66-835 EFFF  J66-811 EF  Male  Male  Female 4 5.17 1.29  Female  J66-836 EF  J37-221 EFBB  Male  Male  Female  6 7.48 1.25  EFWS  No. Birds Total Wt. Average  5 7.37 1.47  11 13.89 1.26  3 4.87 1.62  EFMS  No. Birds 12 T o t a l Wt. 17.33 Average 1.44  5 5.96 1.19  4.13 1.38  EFNS  No. Birds T o t a l Wt. Average  5 6.76 1.35  2 2.36 1.18  3 4.45 1.48  EFNSBB  No. Birds Total Wts Average  7 9.53 1.36  3 3.18 1.06  Totals by Male  No. Birds 29 Total Wt. 40.99 Average 1.41  25 30.56 1.22  3  Male  3 4.50 1.50  Female 13 17.15 1.32  2 2.48 1.24  5 6.76 1.35  5 8.33 1.67  9 11.75 1.31  13 20.57 1.58  27 34.88 1.29  3 2.67 .89  7 8.71 1.24  11 16.68 1.52  4 4.45 1.11  26 38.16 1.47  19 21.79 1.15  4 4.95 1.24  3 4.60 1.53  2 2.45 1.23  11 15.81 1.44  8 9.76 1.22  9 12.91 1.43  1 1.40 1.40  27 39.30 1.45  4 4.68 1.17  28 42.52 1.52  19 24.55 1.29  11 16.86 1.53 9 13.45 1.49  Female  Total  11 12.63 1.14  11 16.86 1.53  16 20.42 1.28  See text regarding feathering c l a s s i f i c a t i o n s of progeny  77 71 113.82 88.16 1.48 1.24  -  -  57  There i s an increase i n weight between the two extremes i n f u l l n e s s of f e a t h e r i n g but that progressive increase i n f u l l n e s s between these extremes were not c o n s i s t e n t l y accompanied by increases i n weight.  Unfortunately the unbalance  of the t a b l e , a r i s i n g from s e v e r a l unrepresented groups, made a c o r r e l a t i o n a n a l y s i s impossible.  Too, the numbers  involved could s c a r c e l y be s a i d to be s u f f i c i e n t t o permit d e f i n i t e conclusions i n any case.  The general i n d i c a t i o n of  the data, however, might be s a i d t o a t l e a s t allow the p o s s i b i l i t y of c o r r e l a t i o n between these two f a c t o r s .  2. Type EFBB Male x Type EFBB and Slow-Feathering Females I n order to i n v e s t i g a t e f u r t h e r the e f f e c t of the bareback c h a r a c t e r i s t i c , i t was decided to mate an EFBB male w i t h poor-feathering females and observe the f e a t h e r i n g of the r e s u l t i n g progeny.  As there was a d i s t i n c t shortage of such  females remaining i n the Rhode I s l a n d Red f l o c k , i t was necessary t o u t i l i z e females of other breeds and a l s o t o use p u l l e t s .  The consequent mating was composed of p u l l e t s  of the f o l l o w i n g breeds and types: Breed Number 2 Rhode I s l a n d Red 3  Type EFFF EFBB  Barred Plymouth Rock  g  ™  New Hampshire  1^  EFBB  ?  2  Note: The EFFF females were included f o r c o n t r o l purposes.  -  58  -  This mating was made at the same time as the r e c i p r o c a l matings ( j u s t discussed) and the progeny of a l l f i v e matings were reared under i d e n t i c a l c o n d i t i o n s .  As was the  case a l s o w i t h the other four matings only small f a m i l i e s were secured which l e f t l i t t l e scope f o r i n d i v i d u a l a n a l y s i s . The r e l a t i v e l y small number of chicks was p r i m a r i l y due to the f a c t that the b i r d s were r a p i d l y going i n t o a molt and consequently " o f f the l a y " to an unfavourable degree.  No chicks  whatsoever were secured from four of the females i n t h i s p a r t i c u l a r mating - i n c l u d i n g both of the c o n t r o l b i r d s .  The  c l a s s i f i c a t i o n of the chicks hatched i s shown i n Table 17. No e a r l y - f e a t h e r i n g male chicks were observed among the progeny of the slow-feathering Barred Plymouth Rocks which, i n s o f a r as the number of progeny permitted, i n d i c a t e d that these females possessed the dominant l a t e f e a t h e r i n g s e x - l i n k e d gene.  I t i s i n t e r e s t i n g to note t h a t ,  aside from the above, there was a f a i r l y evenly d i s t r i b u t e d and extensive v a r i a t i o n i n the progeny of these females.  The  progeny of the slow-feathering New Hampshire a l s o tended t o a s i m i l a r d i s t r i b u t i o n , probably l i m i t e d only by the few number of chicks i n her f a m i l y . The three "Rock" males c l a s s i f i e d as FF- were f u l l f e a t h e r i n g b i r d s with the modifying aspect of r e t a r d a t i o n i n the  development of the feathers on the back and wing bows.  This e f f e c t was most marked at the six-week age and can be p l a i n l y seen on one of the male progeny i n the f a m i l y of female J64-717 at t h i s age by r e f e r r i n g to P l a t e IX, showing  Table 17 C l a s s i f i c a t i o n of the Feathering C h a r a c t e r i s t i c s at S i x Weeks of the Progeny of Experimental Mating #2 Rhode Island Red Male #J66-835 - Type EFBB Rhode Island Red  Breed and Type of Dam  Barred Plymouth Rock  New H'shire  EFBB Type EFBB Type 1-2 Dams Nos. ^ ^ ^ N Feathering fe^s J64-466 J64-485 J64-638 J64-690 J64-702 J64-717 Sex of Progeny o> ? V o* ? o" T o" ? </" T  Type 2  1  EFFF EF EFEFBB  l  1  1*  2  1  FFMT FFST FF-  1 1 1  1-2 2 3 Total  1° 1* 1  3  l 1 2  d  2 1  1  X - Rumpless  2  1  2  5 fa  1 2  l  1  a  3*  2  4  1 1 2  2^  ?  3 1 3  2  1 1§  2 1  2 1  3  11^  9  2  3  J64-801  e  1*  1  Total  ?  *k  2  i  Vs  I 1 4  1  4  - Including one unknown (not early-feathering)  See following page f o r other subscripts  Table 17 - Subscripts a b c d e f g h i J  - Male - Female - Female - Male - Female - Male - Female - Female - Female - Male  k  mm  Male  1  mm  Male  #231 #236 #232 #235 #257 #258 #260  - Type - Type  mm  EFBB — See Plate 7c — See Plate 71c  1-2  — See Plate 71a  Type EFFF — See Plate Xb Type FFMT — See Plate Xlb Type 2  - Type #268 - Type #264 - Type #266 - Type #263 - Type #267  — See Plate I7a  Type 1-2  - Type mm  EF  — See Plate X l l a  EFFF — See Plate XI7c FFMT — See Plate X7b FFMT — See Plate XTIb FFST — See Plate XTIIc 2  — See Plate XTIIIo  -  61—  t h i s family at four, s i x and eight weeks of age. male chick of t h i s f a m i l y which was  (The  s i m i l a r l y affected  other was  l o s t through accident p r i o r to taking the photograph at s i x weeks.)  This observation was,in keeping with the high degree  of c o r r e l a t i o n between feather development of the back and wing bow areas noted generally throughout t h i s experimental work.  The fact that the t a i l development i n these birds  was  appreciably delayed suggested the p o s s i b i l i t y that the r e tardation noted i n the back feathering had been extended p o s t e r i o r l y to include feather development of the t a i l a l s o . However, while such development i n a l l three cases  was  appreciably i n f e r i o r to that of the FF(ST) i n d i v i d u a l s , i t was  not uniformly expressed i n the birds so a f f e c t e d .  The  retarded feathers of the back and wing bow made normal appearance as pin feathers but thereafter developed very slowly and i n a very d i f f e r e n t manner to normal feathers. They did not a t t a i n normal f u l l n e s s p r i o r to molting, at which time they were replaced by normal feathers, but retained t h e i r c h a r a c t e r i s t i c narrowness and tightness even a f t e r reaohing maturity.  They were also observed to possess a yellow-brown  tinge i n pigmentation which gave them a very faded appearance i n contrast to the remainder of the birds' plumage.  As uoth  tne color v a r i a t i o n and retardation of feather development may  D e assumed to have arisen from the s i r e , such a combined  effect i n the progeny suggested a possible close linkage i n tne Rhode Island Red breed between the ractors f o r color and for  the bareback c h a r a c t e r i s t i c .  -  62 -  The f a m i l y produced by dam #J64-717 was t y p i c a l of the wide v a r i a t i o n of f e a t h e r i n g c h a r a c t e r i s t i c s r e s u l t i n g from the Red-Rock cross.  Extensive use was made of t h i s  f a m i l y and that of the slow-feathering Hew Hampshire i n photog r a p h i c a l l y recording progressive stages of feather development of most of the various c l a s s i f i c a t i o n s noted up t o eight weeks of age (see P l a t e s IX t o X I I i n c l u s i v e r e the Rock cross and P l a t e s X I I I t o XVIII i n c l u s i v e f o r the Hampshire cross).  I t should be noted that one female of the Rook f a m i l y  (Plate X)and two females of the Hampshire f a m i l y ( P l a t e XIV) e x h i b i t e d f u l l n e s s of f e a t h e r i n g to an extent found  impossible  of attainment w i t h the U n i v e r s i t y s t r a i n of Rhode I s l a n d Reds even when using Type EFFF breeding stock.  Thus i t would seem  that t h i s f u l l n e s s must have been i n h e r i t e d from the dams i n question and that the genes responsible were masked i n these females by the possession of the dominant a l l e l e f o r slow feathering.  Allowance might a l s o be made f o r the p o s s i b i l i t y  of the presence of an i n h i b i t i o n f a c t o r , the homozygous form of which c o n s t i t u t e s a normal f u n c t i o n of the "bareback" Rhode I s l a n d Red type of f e a t h e r i n g , which l o s t i t s suppressive a c t i o n i n heterozygous c o n d i t i o n i n the progeny.  Should such  be the case, however, the f a c t that slow-feathering female chicks were a l s o observed i n these f a m i l i e s would seem t o suggest t h a t more than one i n h i b i t o r y f a c t o r was involved, that such f a c t o r s d i d not uniformly express themselves i n the phenotype, and that they were independently i n h e r i t e d . The appearance of female c h i c k s of the FF group i n the f a m i l i e s of the Type 1-2 Rock dams and the Type 2 New Hamp-  -  63  -  s h i r e dam might be viewed as lending evidence t o such a possibility.  I n t h i s regard, too, i t should be noted that  the EFFF female c h i c k of the Rock f a m i l y , while extremely f u l l i n f e a t h e r i n g , nevertheless d i s t i n c t l y showed the very pointed t i p s of the secondary f l i g h t feathers which was observed throughout t h i s experiment as being i n d i c a t i v e of t h e presence of i n h i b i t o r s i n a b i r d ' s genetic c o n s t i t u t i o n (see P l a t e X ) .  Be i t as i t may, some aspect of the e l u s i v e  phenomenon termed "hybrid v i g o r " f o r want of a b e t t e r explanat i o n would seem t o be expressing i t s e l f i n the appearance of these females.  C e r t a i n l y t h e i r appearance cannot be  explained s o l e l y on the basis of the possession  of the s e x - l i n k e d  e a r l y - f e a t h e r i n g gene i n h e r i t e d from the s i r e as a l l of the female progeny must be assumed to possess t h i s f a c t o r . Indeed, observations would seem t o i n d i c a t e t h a t the sexl i n k e d a l l e l e s are not i n themselves too important,  parti-  c u l a r l y when a t t e n t i o n i s d i r e c t e d t o the r e l a t i v e f u l l n e s s of f e a t h e r i n g secured i n some of the males (those c l a s s i f i e d i n the FF group i n Table 17) which must be assumed t o have i n h e r i t e d the dominant gene f o r slow f e a t h e r i n g from t h e i r r e s p e c t i v e dams (see P l a t e s X I , XVI and X V I I ) . the possession of t h i s dominant gene,  Aside from  the genetic c o n s t i t u -  t i o n of these dams i s of a very u n c e r t a i n nature i f only, as noted above, by way of the probably masking e f f e c t exerted by t h i s gene over the normal expression of other f a c t o r s affecting feathering.  Thus, as the maternal p o r t i o n of the  genetic c o n s t i t u t i o n of the progeny i s of  necessity  -  64  -  unknown, the extent t o which the bareback c h a r a c t e r i s t i c of the s i r e i s r e f l e c t e d i n the v a r i a t i o n s of f e a t h e r i n g of the progeny cannot be analyzed  satisfactorily.  While only three chicks were secured from one of the Rhode I s l a n d Red Type EFBB females, and four from the other, both e a r l y and l a t e - f e a t h e r i n g i n d i v i d u a l s were represented i n each of the f a m i l i e s .  Although the number of progeny was  i n s u f f i c i e n t t o permit any c o n c l u s i o n being reached r e l a t i v e to the d i s t r i b u t i o n of these types, i t might be allowed that a 1:1 r a t i o was i n d i c a t e d . Retardation of back f e a t h e r i n g of the " e a r l y " c h i c k s s i m i l a r to that already described i n the FF-Rock males, was observed (see P l a t e I V ) .  Due t o the  l i m i t e d s i z e of these f a m i l i e s , no d e f i n i t e conclusion could be made regarding the absence of chicks of the FF group, although the p o s s i b i l i t y of a homozygous i n h i b i t o r y c o n d i t i o n i n the "bareback" genotype, as p r e v i o u s l y expounded, may be o f f e r e d by way of explanation. I t i s of i n t e r e s t t o note that one of the slowf e a t h e r i n g chicks (a female) was not only t a i l l e s s but l a c k ing a pygostyl e n t i r e l y .  The f a c t that t h i s b i r d was of  extremely poor f e a t h e r i n g q u a l i t y (even aside from t h i s rumpl e s s aspect) p l u s , a l s o , the observation that the r e t a r d i n g e f f e c t of the bareback c h a r a c t e r i s t i c appeared to extend p o s t e r i o r l y to a f f e c t t a i l feather development, r a i s e d the question of the p o s s i b i l i t y of a cumulative,  inhibitory,  somal e f f e c t being responsible f o r such a malformity.  3.  65 -  Type EFBB Rhode I s l a n d Red Males x White Leghorn Females Homozygous f o r E a r l y and Normal Feathering  This i n v e s t i g a t i o n was i n s t i g a t e d p r i m a r i l y by the 43 r e p o r t o f McG-ibbon and H a l p i n (1946) i n which reference i s made t o the existence of the "retarded" gene i n the s t r a i n of Rhode I s l a n d Reds a t the A g r i c u l t u r a l Experiment S t a t i o n i n Madison, Wisconsin. This reference i s noted i n f u l l below: "Another v a r i a t i o n , encountered i n S.C.R. I . Reds a t t h i s s t a t i o n , and t e n t a t i v e l y designated as 'retarded due t o i t s s i m i l a r i t y w i t h that f i r s t described by Warren i n Leghorns, i s l i k e w i s e the r e s u l t o f a s i n g l e autosomal r e c e s s i v e gene s u b s t i t u t i o n i n comparison w i t h normal. This character, too, may be recognized i n the day o l d c h i c k , but w i t h greater cert a i n t y a t 2 weeks, and a t 6 weeks i s expressed by a narrow band of feathers on the back while the t a i l feathers approximate i n length those of normal e a r l y f e a t h e r i n g chickens." 44 1  The s i m i l a r i t y of the six-week d e s c r i p t i o n s here reported f o r the "retarded" phenotype and elsewhere reported i n t h i s paper f o r the "EF" phenotype of t h i s U n i v e r s i t y w i l l be noted immediately. E f f o r t s t o s u b s t a n t i a t e t h e existence of such a gene i n the U n i v e r s i t y s t r a i n by means of various matings over the past two years were q u i t e unsuccessful, as has been seen by the r e s u l t s of such matings reported i n t h i s paper i n tabulated form.  More d e t a i l e d observations  made i n t h i s regard (at 1-day, 10-day and 3-week periods)  43.  McG-ibbon, W.H., and H a l p i n , J.G., "Three A l l e l e s A f f e c t i n g Completeness of Feathering i n the Chicken", P o u l t r y Science, 1946, V o l . 25, pp. 406-407 (Abstract only]".  44.  I b i d . , p. 406  and d i s c u s s e d 1)  also  66  elsewhere i n t h i s  f a i l e d to  indicate  that  f e a t h e r i n g r e s u l t e d from the s e r i e s o f g e n e s s u c h as  is  paper (see  the v a r i a t i o n s noted  a c t i o n of a m u l t i p l e  inferred here.  h e r e i n r e p o r t e d was made i n a n e f f o r t of  uncertainty s t i l l For  held relative  preliminary  to  The  A l l three  development  -  l o n g , medium a n d s h o r t -  v e r y r e l i a b l e method o f except i n the At  ten  five  p r e d i c t i o n of  and a t  fairly  the  based upon f l i g h t f e a t h e r  development  type e x h i d t s  long secondaries  wing o u t s t r e t c h e d .  Type E 2 -  EFFF  (#J66-833). flight  d i d not future  feather  prove to  be  a  development reservations. was  differentiation and t a i l  into being  development  w e l l unsheathed. Only the  first  is  (See  arc with  very promient w i t h Plate  f o u r or f i v e  the  the  XlXb) p r i m a r i e s show g o o d  b u t t h e s e l a c k much o f  The s e c o n d a r i e s  with  p r i m a r i e s anu an e q u a l  forming a continuous  The t a i l  development Type E l .  of  one  normal Leghorn f e a t h e r i n g  seven l o n g w e l l - d e v e l o p e d  featners  one  below:  Type E l - T h i s  number o f  of  c h i c k s were c l a s s i f i e d  g r o u p s , E l to E5 ( e x p e r i m e n t a l ) ,  as n o t e d  -  clear-cut differentiation  t h i s time  degree  findings.  extremes and then o n l y w i t h c e r t a i n  d a y s o f age  noticeable  basis  investigation  Rhode I s l a n d R e d  and one EFBB  F e a t h e r i n g c l a s s i f i c a t i o n on the  allelic  pen matings  p h e n o t y p e s were u t i l i z e d i n t h e s e m a t i n g s one E F ( # J 6 6 - 8 1 1 )  in  e l i m i n a t e any  to these  investigation,  w e e k ' s d u r a t i o n were u s e d .  (#J66-835),  Experimental Mating  show u n i f o r m i t y o f  the  length  length  of  which  -  67  -  approximates that of the covert f e a t h e r s . very short pins under the down.  The t a i l i s i n  (See P l a t e XXa)  Type E5 - This type shows both shortened primary  and  secondary f l i g h t f e a t h e r s which, l i k e Type E l , form a continuous  arc with the wing o u t s t r e t c h e d .  The t a i l  develop-  ment, while i n f e r i o r to Type E l , i s a c t u a l l y not as retarded as i t might appear due to the f a c t that the feathers are, by and l a r g e , j u s t beginning to unsheathe and, t h e r e f o r e , do not show i n d i v i d u a l f u l l n e s s e x h i b i t e d by an unsheathed f e a t h e r . (See P l a t e XXIa) Type E4 - This type i s d i f f i c u l t , i f not impossible, t o d i f f e r e n t i a t e from Type E2.  As f l i g h t feather  development i s s i m i l a r i n both types, the only b a s i s of d i f f e r e n t i a t i o n i s i n t a i l development, none of which i s evident i n t h i s type.  However, as such development i n Type  E2 i s extremely l i m i t e d , such a b a s i s cannot be too r e l i a b l e at t h i s age.  considered  D i f f e r e n t i a t i o n i n t h i s regard  becomes very obvious w i t h i n the f o l l o w i n g few days.  (See  P l a t e XXIIb) Type E5 - Extreme r e t a r d a t i o n of f l i g h t feather development would seem t o permit f a i r l y r e l i a b l e c l a s s i f i c a t i o n of t h i s type even at one day of age.  By ten days t h i s  feature i s very n o t i c e a b l e . Much doubt regarding the a c t u a l existence of t h i s type arose from the f a c t t h a t only one chick (a female) was observed i n the e n t i r e hatch.  Further  observations, however, allowed i t s acceptance as a d i s t i n c t  type and gave e v i d e n c e heritable  suspected.  results  of t h e  of  -  s e v e r e r e t a r d a t i o n n o t e d was  p h y s i o l o g i c a l i n n a t u r e as  (See  On t h e b a s i s the  that the  i n o r i g i n and not  originally  68  P l a t e XXIIIa)  the above f e a t h e r i n g  18  Feathering C l a s s i f i c a t i o n at  f  Total  EFFF  3  EF EFBB  cf  ?  3  1  4  4  7  1  2  2  7  3  9  4  3  1  2  14  10  cf  7  1  B y f o u r weeks o f difference  in flight  E3 had been l o s t .  only six  2  At this  cf  ?  3  0  the  significant  1  development between T y p e s E l and  age  the f o r m e r type had seven  s e c o n d a r i e s whereas  feather  differences  feather  difference  i n the  The d i s -  had disappeared e n t i r e l y .  development of b o t h the median  t r a c t a n d the t a i l  i n the  individual  lengths  were q u i t e n o t i c e a b l e ,  l a t t e r b e i n g l a r g e l y one i n f u l l n e s s  feather  long  the l a t t e r had  l o n g p r i m a r i e s and n i n e l o n g s e c o n d a r i e s .  parity in flight However,  cf  age much o f  feather  p r i m a r i e s and t e n l o n g  the  10 D a y s  T y p e E l Type E 2 Type E 3 T y p e E 4 T y p e E 5  cf  dorsal  classifications  t h r e e m a t i n g s a r e shown b e l o w .  Table No.  Sire  was  r a t h e r . t h a n i n the  the  of  a c t u a l number o f  45 feathers  present.  At this  age Type E 2 e x h i b i t e d a r a t h e r  s p a r s e and s p i n d l y t a i l  each f e a t h e r  pointed.  o f b a r b u l e s on t h i s  Apparent l a c k  o f w h i c h was  decidedly  distal portion  -  69 -  gave each feather a very frayed appearance.  Both of these  c h a r a c t e r i s t i c s may be noted i n P l a t e XXb. By t h i s t i m e the secondary f l i g h t feathers were almost of normal length although they s t i l l r e t a i n e d u n i f o r m i t y of length as noted earlier.  Type E4 e x h i b i t e d rudimentary t a i l growth w h i l e  Type E5 was s t i l l q u i t e t a i l l e s s .  Both of these types showed  abnormal secondary f l i g h t feather development, the t i p o f each feather appearing q u i t e pointed i n the e a r l y growth stage and developing a " d r o p l e t " formation by f o u r weeks of age. By s i x weeks o f age Types E l and E3 had l o s t any s i g n i f i c a n t d i f f e r e n c e i n feather development.  At this time  Type EE showed appreciably poorer development of t a i l , back and wing bow development.  Type E4 e x h i b i t e d mostly p i n  feathers i n the d o r s a l feather t r a c t , a few of which were i n the process of unsheathing, and no t a i l development.  Type E5  was s t i l l quite bare on the baok and wing bows and, of course, showed no t a i l growth whatsoever. 45.  I t should be noted here that Male #944 (See P l a t e XIXc) at t h i s age showed r a t h e r superior f e a t h e r i n g f o r Type E l whereas by t h i s t i m e some of the b i r d s c l a s s i f i e d as Type E had developed b e t t e r f e a t h e r i n g than Male #948 (See P l a t e XXIb) so t h a t the o v e r a l l type d i f f e r e n c e s were a c t u a l l y not as great as the photographs accompanying t h i s paper might suggest. However, i n order to d e p i c t c o n t i n u i t y of growth and development of the b i r d s o r i g i n a l l y s e l e c t e d as good examples of t h e i r r e s p e c t i v e types, i t was decided t o use the same i n d i v i d u a l s as p r e v i o u s l y f o r photographic purposes. P l a t e XXIIb i s an exception to the above, a b i r d of a l a t e r hatch being used to f i l l the four-week vacancy i n t h i s s e r i e s o f photographs which arose from the f a c t that Female #919 (See P l a t e X X I I I ) had not been accepted a t t h i s time as r e p r e s e n t a t i v e of a separate c l a s s i f i c a t i o n .  -  70  -  At eight weeks Types E l , E2 and E3 were f o r a l l p r a c t i c a l purposes i n d i s t i n g u i s h a b l e from one another i n f u l l ness of f e a t h e r i n g .  Type E4 showed good back and wing bow  f e a t h e r i n g although not a l l the p i n feathers i n these areas had completely unsheathed.  The t a i l feathers were s t i l l very  short and mostly i n the p i n stage.  Type E5 e x h i b i t e d  little  advancement i n f e a t h e r i n g and presented e s s e n t i a l l y the same appearance as a t s i x weeks.  No t a i l development was observed  i n t h i s b i r d u n t i l twelve weeks of age. As the above-noted r e s u l t s warranted f u r t h e r i n v e s t i gation, both o f the Type EFBB males p r e v i o u s l y used i n t h i s experimental work were mated t o Leghorns which were trapnested for  progeny i d e n t i f i c a t i o n purposes.  Two hatches were  secured from these matings, the f i r s t on January 2nd and the second on January 21st of t h i s year.  The r e s u l t i n g chicks  were subjected to rigorous o b s e r v a t i o n and two c l a s s i f i c a t i o n s , a d d i t i o n a l to the f i v e p r e v i o u s l y r e p o r t e d , were adopted to permit f i n e r d i s t i n c t i o n i n v a r i a t i o n o f feather development Type E l - 2 and Type E4X.  The former was adopted i n order to  a l l o w f o r v a r i a t i o n p r e v i o u s l y included i n Types E l and E3, while the l a t t e r s i m i l a r l y took i n t o c o n s i d e r a t i o n v a r i a t i o n p r e v i o u s l y i n c l u d e d i n Type E2. Type E l - 2 gave independent c l a s s i f i c a t i o n to those chicks which e x h i b i t e d a more r a p i d decrease i n length of the secondary f l i g h t feathers proximal t o the body than was noted i n others (which r e t a i n e d the c l a s s i f i c a t i o n E l ) i n a manner s i m i l a r to t h a t p r e v i o u s l y discussed i n connection w i t h the  -  -  71  -  Rhode I s l a n d Red chicks (see P l a t e 1 - b and c ) .  Such a  tendency i s , of course, quite normal to a c e r t a i n degree as a r e s u l t of the progressive manner i n which these f e a t h e r s make t h e i r appearance i n plumage development (see P l a t e XlXa) and, because of the r i g i d s p e c i f i c a t i o n s demanded f o r Type E l i n c l a s s i f y i n g these c h i c k s , i t was considered q u i t e probable that many, i f not a l l , of those typed E l - 2 may have been normal-feathering b i r d s . C e r t a i n l y none e x h i b i t e d the severe degree of r e t a r d a t i o n described by Warren et a l as the expression of the "retarded" gene i n Leghorns. The i n t r o d u c t i o n of Type E l - 2 may be considered to be the main reason f o r the l a c k of r e p r e s e n t a t i o n (with the exception of one male c h i c k ) of Type E3 i n the r e s u l t s of these matings, as shown i n Tables 19 and 20.  Too,  i t must be  remembered, as noted p r e v i o u s l y , that by four weeks of  age  the s i g n i f i c a n t d i f f e r e n c e s between Types E l and E3 have l a r g e l y disappeared.  While an appreciable number of chicks  were c l a s s i f i e d t h i s type at two days of age, t h i s number had decreased r a p i d l y by ten days of age, had p r a c t i c a l l y d i s appeared by three weeks and had been reduced to one by f o u r weeks. About two-thirds of those o r i g i n a l l y so c a l s s i f i e d underwent a t r a n s i t i o n i n typing to Type E l - 2 (some of which subsequently had been c l a s s i f i e d Type E l by four weeks), the remaining o n e - t h i r d d i r e c t l y from Type E3 to E l . While some doubt may  be harboured regarding the a c t u a l existence of t h i s  c l a s s i f i c a t i o n i n the l i g h t or i t s elusiveness ana  unpredict-  able development, sucn c n a r a c t e r i s t i c s may be explained by  -  72  -  the p o s s i b i l i t y that the e i r e o t s or the causative f a c t o r ( s ) may  be of very l i m i t e d duration.  that sex may  I t should be noted, too,  p o s s i b l y be involved i n t h i s p a r t i c u l a r type as  males seemed to be more prone than females,both t i o n and d u r a t i o n of t h i s phenotypic  i n representa-  classification.  As noted above, Type E4X i n e f f e c t gave f u r t h e r d i f f e r e n t i a t i o n i n f e a t h e r development between Types E2 and E4.  Observations  c a r r i e d out would seem to i n d i c a t e that  these three c l a s s i f i c a t i o n s represent a s e r i e s of progressive degrees of i n h i b i t i o n i n feather development, p a r t i c u l a r l y that of the t a i l .  I n regard to t h i s l a t t e r aspect,  they  e x h i b i t i d e n t i c a l development of the i n d i v i d u a l feather i n the manner p r e v i o u s l y described f o r Type E2, d i f f e r i n g only i n the time of appearance.  A l l e x h i b i t a p e c u l i a r physio-  l o g i c a l abnormality i n feather development which suppresses eruption and e a r l y growth a f t e r which the e f f e c t  disappears.  This c h a r a c t e r i s t i c would seem to be d i r e c t l y r e l a t e d t o the aberrant formation of the t i p s of the t a i l feathers and  those  of the secondary f l i g h t feathers i n these p a r t i c u l a r f e a t h e r tracts.  Following t h i s i n i t i a l stage of suppression,  develop-  ment i s quite r a p i d although a l l three types continue to show progressive stages of t a i l feather l e n g t h up to t e n weeks of age.  The r e s u l t a n t type of feather d i f f e r s very markedly  from the " j u v e n i l e " type of t a i l feather of Types E l , E l - 2 and E3, being quite broad i n p h y s i c a l dimension and resemb l i n g adult plumage i n contrast t o the smaller and narrower feather of these l a t t e r types.  Table 19 Progeny of Rhode Island Red S i r e J66-833 - Experimental Mating #3 Fea1 ihering C l a s s i f i c a t i o n alb 4 Weeks Dam  E] o*  381  El-2  ?  1  E3  a"  ?  1  1  804  o"  E2  ?  E4X  o" ?  o*  H13-262  1  J65-820  2  2  1  1  2  1 1  1  2  1  J65-838  2  40  lb  J65-849  1  2  J65-879  1  3*  J65-881  3  2  J65-884  2  J65-956 J66-066  2  2  0*  %  2  2  1-  1  1  1  l  1  1  3  1  5  5  1  1  4  8  6  6  7  5  3  2  5  2  2  8  5  8  3  0  3  4  0  1  5  55  47  1  1  2 e  1  1  2  3  3  1  1  1 2^  1 8  2d  1  2 19  e  3  1 1  11  Total  E5  *** ¥  o*  1  2 11  1  3  3  1  J66-115 Total  2  L  1  H13-236 1  ?  -  1  H13-256  E4  X  0  7  2  14  12  See Table 20 re subscripts  3  11  l 0  3  c  Table 20 Progeny of Rhode Island Red S i r e J37-221 - Experimental Mating #5 Feathering C l a s s i f i c a t i o n at 4 Weeks Dam  El-2  El  </  ¥  340  E2  E3  ¥  ¥  ¥  E4X o"  E4 ¥  /  Total  E5 ¥  o"  ?  i  445  3  1  H13-345  l  i a  l  a  l*  i*  ¥  0  1  5  1  1  2  J65-8S4  2  i  2  2  4  2  J65-872  2  2  3^  3b  5  6  J65-893  1  2  1  2  J65-991  2  3  2  4  4  7  J66-055  2  2  4  1  6  3  J66-092  2  1  2  2  3  12  10  28  27  Total  15  Subscripts applicable to Table 19 also  16  0  0 a b e d e  -  •1  I  "Retarded Including Including Including Rumpless  0  0  0  0  0  0  back" at 8 weeks one "retarded back" at 8 weeks one ^bareback" at 8 weeks two "barebacks" at 8 weeks  -  75  -  A major dominant i n h i b i t o r would appear to be  respon-  s i b l e f o r the appearance of these c l a s s i f i c a t i o n s which, i n c l u s i v e of Type E5, represented f i f t y per cent of the progeny not o n l y on an o v e r a l l basis (52/102) but a l s o r e l a t i v e to sex d i s t r i b u t i o n (24/55 males, 28/47 females).  Such r e s u l t s  i n d i c a t e d the male b i r d to be heterozygous f o r such an i n hibitor.  Further d i f f e r e n t i a t i o n , represented by these four  c l a s s i f i c a t i o n s , would seem to be i n d i c a t i v e of the presence of a d d i t i o n a l i n h i b i t o r y m o d i f i e r s a c t i n g i n a manner i n suppressing t a i l development.  cumulative  The f a c t that Type  E5 was represented only by female c h i c k s , plus the f u r t h e r observation that the percentage of females increased w i t h each progressive stage of suppression, would suggest that these l a t t e r i n h i b i t o r y m o d i f i e r s were a l s o equal i n t h e i r d i s t r i b u t i o n between the sexes but that a f u r t h e r i n h i b i t o r y f a c t o r , of a r e c e s s i v e s e x - l i n k e d nature and capable of expression only i n the heterogametic  female, was  superimposed  upon t h i s genetic background to give the r e s u l t s obtained. Reference to Table No. 19, showing the c l a s s i f i c a t i o n of the progeny of Male J66-833, w i l l g r a p h i c a l l y i l l u s t r a t e t h i s point.  I t i s to be noted that a s i m i l a r d i s t r i b u t i o n i n the  progeny of t h i s s i r e r e s u l t i n g from the p r e l i m i n a r y mating was secured (see Table No.  18).  Assuming the p o s s i b i l i t y of the existence of isuch a s e r i e s of i n h i b i t i n g f a c t o r s , a n a l y s i s of the r e s u l t s of t h i s mating would seem t o i n d i c a t e a f u r t h e r p o s s i b i l i t y of such f a c t o r s being independently  i n h e r i t e d and, i n the absence of  the major dominant f a c t o r , to be responsible f o r the  variations  i n feather  classifications it in  the  will  feathering  of  the  those observed  The r e s u l t s of  of  same p h e n o t y p e genetic  this  indicate  i n the  cumulative a c t i o n of  other mating  the  were,  ficient  nevertheless,  a s e r i e s of  would appear t h a t  not  foster  of  a genetic  the  such f a c t o r s .  were o b s e r v e d , b a b l e , as  this  observed  viewed  as  (out  The f a c t  of  but a l s o  as  noted the  former was  suf-  "bareback" sufficient dominant  feathering,  would n o t  that  a total  to  to.the  by t h e  a p p e a r to  cumulative  of  be  i n the absence o f  fifty-five)  chicks  impro-  to r e p r e s e n t  o n l y two c h i c k s  independent  such a cumulative e f f e c t ,  their  the  the m o d i f i e r s  supporting such a theory and,  f u r t h e r i n d i c a t i o n of  the  A s o n l y Type E2 s l o w - f e a t h e r i n g  hypothesis  of  of  in  p o s s e s s e d by the  progeny,  maximum i n h i b i t o r y a c t i o n p o s s i b l e  were  matings  while both of  s u c h a p h e n o t y p e m i g h t be c o n s i d e r e d  dominant f a c t o r .  two  different  phenotypic  condition in his  action  The  l a t t e r m a l e was l a c k i n g  the b i r d h i m s e l f  "normal" L e g h o r n type  the  inhibiting factors  this  autosomal of  not  discussed.  possibility  possession of  o n l y to p r e s e n t  classification  variations  just  of  two m a l e s ,  A s s u m i n g the  nevertheless,  the  shown i n T a b l e N o . 20.  major dominant i n h i b i t o r s u p p o s e d l y but t h a t ,  that  overall results  that  (EFBB),  early-feathering  characteristics.  mating are  constitutions.  it  i n the  p r o g e n y o f M a l e J37-221 d i d  s i m i l a r i t y i n the  w o u l d seem t o  above,  development  be i m m e d i a t e l y n o t i c e d  feathering  parallel  lack  of  76 -  of  the  this  might a l s o  in addition,  inheritance.  as  the  major type be a  Furthermore,  i n conjunction with the  assumed  -  sex-linked of  the  i n h i b i t o r , m i g h t be o f f e r e d  difference  which e x h i b i t e d J66-833  -  77  (male  noted  i n the  percentages of  slow f e a t h e r i n g  24/55 -  While there  as a c a u s a t i v e  i n the  44%; f e m a l e  28/47 -  R e t a r d a t i o n , where n o t i c e d , that  Red-Rook c r o s s  Usually only  the  development  of  c e n t r a l p a i r of noticeable  feathers  the  at  u s u a l l y showed  feathering  of  manner t h r o u g h o u t  only the  f o r m e r was o b s e r v e d  mating.  This  of  to  this  appearance of from the  of  completely cross.  the  would seem t o  presence  the  so  weeks o f  at  affected. age  and h a d  of  e i g h t weeks o f  c h i c k s from the the  possible  to  i n three  inhibitory factors  age  this of  pro-  such a s n o t e d  while  least  i n the  on t h e earlier.  in  chicks the  T y p e E l - 2 male  explained  back  other-  a s s u m p t i o n was  the  and  necessity  major dominant i n h i b i t o r a t back f e a t h e r i n g  the  pin  B o t h r e t a r d a t i o n of  indicate  An e x c e p t i o n  to  Barebacked b i r d s , on  i n the  suppress  bareness  was  the  progeny of Male J66-833  o t h e r m a l e w h i c h m i g h t be  cumulative  in  feathers.  back appeared i n a r a t h e r  miscuous  order  six  i n the median d o r s a l t r a c t  and b a r e n e s s  posteriorly  only a narrow streak  by t w e l v e .  the  was  was s i m i l a r  central t a i l  feathers  are not f u l l y feathered  of  extend  d i s a p p e a r e d b y n i n e weeks.  other hand,  t h e modus o p e r a n d i  p r e v i o u s l y d e s c r i b e d when d i s c u s s i n g  R e t a r d a t i o n was m o s t largely  development  a n d was o b s e r v e d t o  s i m i l a r l y suppress  Male  a p p e a r e d to b e some c o r r e l a t i o n between  quite  to  sexes  60%).  and t a i l  appearance  two  progeny of  back f e a t h e r i n g obscure.  the  factor  progeny  basis The  of  fact  that  -  these barebacked progeny appeared i n the  feathering  group of  theory that to  78  c h i c k s would a l s o  different  genetic  t h e EFBB p h e n o t y p e  as  constitutions  and e f f e c t i v e l y  support  may g i v e  presupposed e a r l i e r ,  apparently having i n h e r i t e d a l l sire  seem, t o  early-  these  inhibitory factors  representing  the  same  the rise  chicks from  the  phenotype.  Discussion The f o r e g o i n g r e s u l t s have of the  shown t h a t  the  progeny of  expression  on t h e  aberrations  basis  domestic  i n the  genetic factors  of past  state  e x p e r i m e n t a l work  feathering  characteristics  To the  definitely  w h i c h c a n n o t be  research relative extent  that  were u t i l i z e d i n s e c u r i n g t h e s e to  this  e a r l y - f e a t h e r i n g barebacked R I R ' s  of  fowl.  of  the  degree  to  explained  feathering  inter-breed  results,  indicate  it  is  to which they  in  the  matings not  are  possible  inherent  i n t h e RIR b r e e d i n g e n e r a l and i n t h e b a r e b a c k c h a r a c t e r istic  in particular.  a p p e a r to  inject modifications  characteristics the  C e r t a i n l y i n t e r - b r e e d matings  of  opinion that  the  into  the  overall  r e s u l t i n g progeny.  t o assume  s i m i l a r i t y of  would  feathering  The w r i t e r i s genetic  of  constitutions  o f v a r i o u s b r e e d s may p r o v e t o be v e r y m i s l e a d i n g  in  inter-  preting resultant  in  this  regard is  the  i n the r a t e  of  data.  A rather pertinent  phenomenon o f t h e feathering  of  the  sexually  point  dimorphic  American breeds  aspect in  contrast  -  to  the  u n i f o r m i t y of  breeds.  research  breeds  i n this  -  feathering  The d i s t i n c t  in different  79  found i n the M e d i t e r r a n e a n  possibility  is,  field,  perhaps,  of major g e n e t i c too  r e a d i l y overlooked  p a r t i c u l a r l y i n the  in fostering  genetic  theory r e l a t i v e  W h i l e much i n f o r m a t i o n r e l a t i v e breeds  h a s been  evidence  lost  available  to  the  major g e n e t i c  to  permit the  period.  Certain feathering  example,  are a t t r i b u t a b l e aside  or t i g h t n e s s  of  heritable an o r i g i n .  the R I R ' s Game.  The a c t i o n  suppressing  of  not  the  oi  tne RIR,  lor  too,  closeness other  link  exists  the  is,  data  such  between however, in  i n h i b i t o r y aspect  arises  i n the  this of  from the Red M a l a y in  i n t e r - b r e e d mating with  f o r b o t h e a r l y and n o r m a l  s i m i l a r l y expressing  that  intervening  assumed m a j o r i n h i b i t o r  t a i l development  L e g h o r n s homozygous while  the  be  may be t r a c e d t o  Analysis of  genetic c o n s t i t u t i o n  anything  w o u l d seem  the White L e g h o r n ,  p a p e r w o u l d ' s u g g e s t t h a t much o f  various  sufficient  undoubtedly i t s  feathering  o f much c o n j e c t u r e .  the  R e d M a l a y Game a n c e s t r y  J u s t how c l o s e a n a n c e s t r a l say,  feathering.  that  i n the  Quite presumably,  affecting  t h e R e d M a l a y Game a n d , a matter  is  been  still  Thus i t  evolved  its  to  i n many c a s e s ,  characteristics  from c o l o r ,  plumage.  factors  to  is  assumption  past.  changes may h a v e  has  o r i g i n of  there  must,  very distant  among w h i c h ,  the  in antiquity,  r e s e m b l i n g a common a n c e s t o r relegated  to  in  relatively  i n d i s c r i m i n a t o r y manner i n w h i c h c r o s s b r e e d i n g utilized  variations  itself  feathering,  i n t h e Rhode I s l a n d Red  - 80 phenotypes,  may be c o n s i d e r e d t o  On t h e i m e n t a l work, "Theory of breed.  it  of  the  data obtained  w o u l d seem p e r m i s s i b l e  Inhibitors" relative  to  "While f u r t h e r r e s e a r c h i s  obtain definite and,  basis  be i n d i c a t i v e  proof of  subsequently,  properties, in this  the  minor i n h i b i t o r s linked  of  this  which appears  to  postulate  such  inheritance work i n d i c a t e -  sex-linked  normal type  of  Leghorn f e a t h e r i n g  ment when a s s o c i a t e d linked recessive not  constitution  w i t h the  as  for  the  two m i n o r i n h i b i t o r s a r e c a p a b l e  gene.  Their  either  i n the  cumulative  presence  action  is  type  i n i n t e r - b r e e d matings,  appearance  of  this  type of  R e d f l o c k w o u l d seem t o  of  tail  form of  1  the  indicate  that  sex-  extreme  or  the  that  rarity  do n o t  The  cumulative  major  i n t h e Rhode they  is  gene.  of  t h e T y p e E 2 (FFMT)  feathering  develop-  phenotypes  independent  but the  the  A t any r a t e - i t  o r absence of  to  t h e Rhode  be dominant t o  a p p a r e n t l y e q u a l to  major i n h i b i t o r i n g i v i n g r i s e  sex-  The m a j o r  early-feathering of  two  and a f o u r t h  i n t h e Rhode I s l a n d Red  w h i c h a r e a l s o homozygous  aotion,  gene.  presence  their  i n suppressing  homozygous  early-feathering  s i m i l a r l y expressed  and t o  genetic  one m a j o r and  i n h i b i t o r w o u l d seem t o be a n o r m a l complement Island Red's genetic  to  inhibitors  the  are concerned,  be a r e c e s s i v e  a  and o t h e r  an unknown n a t u r e i n s o f a r  or autosomal p r o p e r t i e s  exper-  admittedly required  four i n h i b i t i n g factors of  in this  regard.  t h e Rhode I s l a n d R e d  e x i s t e n c e of  t h e i r mode of  results  breed of  the  to  in this  factor. the  phenoof  Island express  -  81  -  t h e m s e l v e s i n a l i k e manner i n i n t r a - b r e e d m a t i n g s . may be p o s s i b l e , for  the  feather  variations development  s i m i l a r manner action ations, to  however,  is  the  while  noted data  to  in this  flight  paper.  indicates  is  that  responsible  and  tail  I n a somewhat  their  independent  The f o u r t h i n h i b i t o r i s f o r the  back f e a t h e r i n g  bareback phenotype or the It  would appear  plus  sex-linked  inhibitor,  difficulty  that  poor f e a t h e r i n g p e r s i s t e n c e of  has  the  to  to  the  the be  apparent  "masked" t o  retarded  and o f  the  major  tendency at  of  least  p l a y e d a prominent  role  in  in eliminating  the  the  the the  t h e Rhode I s l a n d R e d a n d i n  m i l i t a t i n g aspect of  the  an  apparent recessiveness of  been e x p e r i e n c e d of  be  inhibitors. that  has  quality the  of  appear  the  when a s s o c i a t e d e i t h e r w i t h t h e  two m i n o r  degree,  appearance  in  believed  in individual action,  m a j o r and m i n o r i n h i b i t o r s appreciable  classific-  t h e m a j o r gene t h e y  t h e E4X and E 4 c l a s s i f i c a t i o n s  primarily responsible  inhibitor  action  found i n secondary  i n conjunction with  Leghorn c r o s s .  of  their  e x p r e s s e d i n t h e E l - 2 and E 3 f e a t h e r i n g  give r i s e  type  that  It  the  "bareback".  Conclusions 1.  I n h i b i t i n g f a c t o r s , p o s s i b l y p e c u l i a r t o the Rhode I s l a n d R e d a n d a r i s i n g f r o m i t s R e d M a l a y Game a n c e s t r y , were i n d i c a t e d i n the g e n e t i c c o n s t i t u t i o n of t h i s b r e e d ; these f a c t o r s g i v e r i s e t o the " b a r e b a c k " c h a r a c t e r i s t i c .  -  82  -  £.  A major i n h i b i t i n g f a c t o r , a p p a r e n t l y not expressed i n Rhode I s l a n d Red f e a t h e r i n g p h e n o t y p e s , i s d o m i n a n t t o homozygous e a r l y - f e a t h e r i n g n o r m a l L e g h o r n t y p e o f feathering. I n s u c h a c r o s s i t e x p r e s s e s i t s e l f by r e t a r d i n g t a i l development i n a s p e c i f i c manner. It e x e r t s a p h y s i o l o g i c a l a c t i o n i n the e a r l y development o f s e c o n d a r y f l i g h t and t a i l f e a t h e r s i n s u p p r e s s i n g e r u p t i o n and e a r l y g r o w t h a f t e r w h i c h i t s a c t i o n seems to cease. I t s e f f e c t c a n be n o t e d by t h e m a l f o r m a t i o n of the t i p s of these f e a t h e r s .  3.  Two m i n o r i n h i b i t o r s , c a p a b l e o f i n d e p e n d e n t o r c u m u l a t i v e a c t i o n e i t h e r i n the presence or absence of the major f a c t o r , are a l s o i n d i c a t e d i n the L e g h o r n c r o s s . T h e i r c u m u l a t i v e a c t i o n i s e q u a l t o t h a t of the major i n h i b i t o r when t h e l a t t e r gene i s n o t p r e s e n t . It is b e l i e v e d t h a t t h e i r a c t i o n i n c o n j u n c t i o n w i t h the major f a c t o r probably i s r e s p o n s i b l e f o r the v a r i a t i o n s i n s e c o n d a r y f l i g h t and t a l l d e v e l o p m e n t n o t e d i n Rhode I s l a n d Red c h i c k s .  4.  E x p e r i m e n t a l work was i n s u f f i c i e n t t o d e m o n s t r a t e w h e t h e r t h e s e t h r e e genes are autosomal o r s e x - l i n k e d i n n a t u r e .  5.  A f o u r t h i n h i b i t i n g f a c t o r a p p e a r e d t o be a r e c e s s i v e s e x - l i n k e d gene and t o be p r i m a r i l y r e s p o n s i b l e f o r r e t a r d e d b a c k f e a t h e r i n g when a c t i n g a l o n e and f o r t h e " b a r e b a c k " when a c t i n g i n c o n j u n c t i o n w i t h t h e m a j o r i n h i b i t o r o r t h e two m i n o r i n h i b i t o r s .  6.  F u r t h e r r e s e a r c h work i s r e q u i r e d t o d e f i n i t e l y a i n t h e e x i s t e n c e o f t h e s e g e n e s and t h e i r mode inheritance.  ascertof  -  83  -  BIBLIOGRAPHY A m e r i c a n P o u l t r y A s s o c i a t i o n , I n c . , T h e , The A m e r i c a n S t a n d a r d of P e r f e c t i o n , D a v e n p o r t , Iowa, E d i t e d by t h e C o m m i t t e e on S t a n d a r d s and P u b l i s h e d b y the A s s o c i a t i o n , r e v i s e d , 1945. 4 9 £ pp. Canada,  P a r l i a m e n t , H o u s e o f Commons, " R e g u l a t i o n s Made Under the P r o v i s i o n s o f the L i v e S t o c k and L i v e S t o c k P r o d u c t s A c t , C h a p t e r 120 o f t h e R e v i s e d S t a t u t e s o f Panada, 1927, R e s p e c t i n g the G r a d i n g and M a r k i n g o f D r e s s e d P o u l t r y , a s P u b l i s h e d i n t h e C a n a d a G a z e t t e , November, 1 9 2 8 , a n d I n c o r p o r a t e d Amendments i n t h e C a n a d a G a z e t t e , D e c e m b e r , 1 9 3 1 , a n d November, 1934".  Danforth,  C . H . , "Two F a c t o r s I n f l u e n c i n g F e a t h e r i n g i n C h i c k e n s " , G e n e t i c s , B r o o k l y n , New Y o r k , B r o o k l y n B o t a n i c G a r d e n , 1929, v o l . 14, p p . 256-269.  D a r r o w , M . I . , " R e l a t i o n o f t h e D a y - o l d Wing F e a t h e r D e v e l o p ment t o F e a t h e r i n g a t t h e B r o i l e r A g e " , P o u l t r y S c i e n c e , S t i l l w a t e r , Oklahoma, P o u l t r y S c i e n c e A s s o c i a t i o n , 1941, V o l . 20, p . 458, A b s t r a c t o n l y . D a r r o w , M . I . , and W a r r e n , D . C , "The I n f l u e n c e o f Age On E x p r e s s i o n o f Genes C o n t r o l l i n g R a t e o f C h i c k F e a t h e r i n g " , P o u l t r y S c i e n c e . 1944, V o l . 23, pp. 199-212. Glazener,  E . W . , a n d J u l l , M . A . , "Rate o f F e a t h e r i n g a n d Ten-Week B o d y W e i g h t O b s e r v a t i o n s i n S t r a i n s D i f f e r i n g i n Shank L e n g t h " , P o u l t r y S c i e n c e . 1946, V o l . 2 5 , p p . 4 3 3 - 4 3 9 .  Hays,  F . A . , " E a r l y a n d L a t e F e a t h e r i n g i n Rhode I s l a n d R e d s " , A m e r i c a n N a t u r a l i s t , New Y o r k , S c i e n c e P r e s s , 1932, V o l . 66, p p . 286-287.  Hays,  F . A . , a n d S a n b o r n , R . , B r e e d i n g Rhode I s l a n d R e d s f o r R a p i d F e a t h e r i n g , 1942, M a s s a c h u s e t t s A g r i c . E x p . S t a . B u i . N o . 396.  Jaap,  R . G . , and M o r r i s , L . , " G e n e t i c D i f f e r e n c e s i n E i g h t week W e i g h t and F e a t h e r i n g " , P o u l t r y S c i e n c e . 1937, V o l . 16, p p . 4 4 - 4 8 .  Jones,  D . G . , and H u t t , F . B . , " M u l t i p l e A l l e l e s A f f e c t i n g F e a t h e r i n g i n the Fowl", J o u r n a l o f H e r e d i t y , W a s h i n g t o n , A m e r i c a n G e n e t i c A s s o c i a t i o n , 1946, V o l . 37, p p . 197-205.  -  84  -  K i n u g a w a , Y . , "On t h e S e x - l i n k e d I n h e r i t a n c e o f T a i l F e a t h e r i n g " , P r o c . F o u r t h W o r l d ' s P o u l t r y Congress and E x p o s i t i o n , Ottawa, 1927, p p . 105-111. Lloyd,  E . A . , " B r e e d i n g f o r Meat and E g g P r o d u c t i o n " , P r o c . S e v e n t h W o r l d ' s P o u l t r y Congress and E x p o s i t i o n , C l e v e l a n d , O h i o , 1939, p p . 4 8 3 - 4 8 7 .  Lloyd,  E . A . , "Selection for Early F u l l Feathering, Rapid G r o w t h and B o d y C o n f o r m a t i o n " , C a n a d a P o u l t r y m a n , New W e s t m i n s t e r , B . C . , F a r m P a p e r s L t d . , 1 9 4 1 , V o l . 28, p p . 3 - 5 .  Martin,  J . H . , "Rate o f F e a t h e r Growth i n B a r r e d P l y m o u t h Rock C h i c k s " , P o u l t r y S c i e n c e , 1929, V o l . 8, pp. 167-183.  McClary,  C . F . , and B e a r s e , G . E . , " R e c e s s i v e A u t o s o m a l F a c t o r f o r Slow Plumage", P o u l t r y S c i e n c e , 1941, V o l . 20, pp. 466-467. Abstract only.  McGibbon,  Radi,  W . H . , and H a l p i n , J . G . , "Three A l l e l e s A f f e c t i n g Completeness o f F e a t h e r i n g i n the C h i c k e n " , P o u l t r y S c i e n c e , 1946, V o l . 2 5 , p p . 4 0 6 - 4 0 7 . Abstract only.  M . H . , and W a r r e n , B . C . , " S t u d i e s on t h e P h y s i o l o g y and I n h e r i t a n c e o f F e a t h e r i n g i n t h e G r o w i n g Chick", J o u r . A g r i c . Research, Washington, U . S . G o v t . P r i n t i n g O f f i c e , 1938, V o l . 5 6 , p p . 6 7 9 - 7 0 5 .  Serebrovsky, A . S . , "Crossing-over I n v o l v i n g Three SexL i n k e d - Genes i n C h i c k e n s " , A m e r i c a n N a t u r a l i s t , V o l . 56, p p . 571-572. Warren,  D . C , "Inheritance of Rate of F e a t h e r i n g i n P o u l t r y " , J o u r n a l of H e r e d i t y , 1925, V o l . 15, p p . 1 3 - 1 8 .  Warren,  D . C , "Retarded F e a t h e r i n g i n the F o w l . A New F a c t o r A f f e c t i n g t h e Manner o f F e a t h e r i n g " , J o u r n a l o f H e r e d i t y , 1933, V o l . 2 4 , p p . 4 3 1 - 4 3 4 .  Warren,  D . C , and P a y n e , L . F . , " I n f l u e n c e o f the E a r l y f e a t h e r i n g Gene Upon a C h i c k ' s G r o w t h " , P o u l t r y S c i e n c e , pp. 101-192.  -  85  -  Other L i t e r a t u r e C i t e d  Payne,  L . F . , and S c o t t , H . M . , " I n t e r n a t i o n a l P o u l t r y G u i d e f o r F l o c k S e l e c t i o n " , Kansas C i t y , Mo. I n t e r n a t i o n a l B a b y C h i c k A s s o c i a t i o n , 1934, 142 p p . , c i t e d i n R . G . J a a p and L . M o r r i s , " G e n e t i c D i f f e r e n c e s i n E i g h t - w e e k W e i g h t and F e a t h e r i n g " , P o u l t r y S c i e n c e , 1937, V o l . 1 6 , p p . 4 4 - 4 8 .  Saharova,  L . N . , G e n e t i c s of t h e R a t e of F e a t h e r i n g , Mem. A n i k o w o S t a t i o n , e d i t e d by K o l t z o f f , p . 130, c i t e d i n F . A . H a y s a n d R . S a n b o r n , B r e e d i n g Rhode I s l a n d Reds f o r R a p i d F e a t h e r i n g , 1942, M a s s . A g r . E x p . S t a t i o n B u i . N o . 396, p . 2 .  F E A T H E R  D E V E L O P M E N T I N  RHODE  I S L A N D  P L A T E S  I  TO  I N C L U S I V E  REDS  V I I  PLATE  Plate  I  l a - M a l e #270  Showing the normal range i n f e a t h e r development o b s e r v e d throughout the f l o o k at ten d a y s o f age  P L A T E  P l a t e  I  # 2 6 9  (?)  l  a -  -  4  w e e k s  # 2 7 0  -  o f  # 2 7 1  {cf)  (  f  I  I  a g e  -  # 2 7 2  -  # 2 7 3  {cf)  )  -  # 2 7 4  ( ? )  ( < f l  >  A  t y p i c a l  f a m i l y  R h o d e  s h o w i n g  d e v e l o p m e n t t h e  f l o c k  e i g h t  f o u n d a  t  w e e k s  w i n g b a n d  I s l a n d  n o r m a l  t h r o u g h o u t  f o u r , o f  s  a g e .  n u m b e r s  a  r  s e c u t i v e  o r d e r  f r o m  r i g h t  n o t e d  i  t h e  a s  f e m a l e s  u p p e r  r o w  i  n  i  x  a n d  N o t e e  i  n  P l a t e  t h a t c o n -  l e f t  P l a t e  I  c o n s t i t u t i n g n  R e d  f e a t h e r  l  i  e  .  t l  o a  t  h  , e  -  # 2 7 5  (0.)  PIATE I I I  PIATE IV Type EF - T y p i c a l male ana female development noted a t s i x and eight weeks of age  PIATE V  PLATE YI  PLATE  VII  Showing t y p i c a l Type 1 - 2 and Type EF c h i c k s r e s u l t i n g from the EFBB x EFBB mating - see Experimental Mating 2 i n t e x t Note: B i r d s i n the same order i n a l l three p i c t u r e s  F E A T H E R  D E V E L O P M E N T  I N R H O D E  I S L A N D  R E D  A N D B A R R E D  P L Y M O U T H  R O C K  C R O S S  P L A T E S  V I I I  T_0  I N C L U S I V E  Z. X I  I  PIATE V I I I  Showing the f a m i l y of Tyne EFBB BPR dam #J64-638 (one Type EF male, two Type 2 females) at four, s i x and eight weeks of age. S i r e : Type EFBB RIR #J66-833 (See Experimental Mating #2)  PIATE IX  P l a t e IXa - 4 weeks of age  ^^^^^  ^^^^^  Showing f e a t h e r i n g types r e s u l t i n g from the inter-breed mating using a BPR Type 1-2 dam (#J64-717) and a RIR Type EFBB male (#J66-833) a t f o u r , s i x and eight weeks of age. Note that the b i r d s i n P l a t e s IXb and LXc are i n the f o l l o w i n g order reading from l e f t t o r i g h t : 256 - Type 1-2 female 258 - Type FFMT male #257 - Type EFFF female #259 - Type FF- male #260 - Type 2 female  Type EFFF ( E l ) Female #257 showing an extreme f u l l n e s s of f e a t h e r i n g found impossible of attainment i n the U.B.C. s t r a i n of Rhode I s l a n d Reds. Note the degree of f u l l n e s s at four weeks i n contrast t o i t s f u l l s i s t e r s (Plates IX and X I I ) .  PLATE X I  P l a t e X I a - 4 weeks of age  •  Type FFMT (E2) Male #258 showing the type of f e a t h e r i n g commonly found i n Orpingtons and New Hamps h i r e s (see P l a t e X V I I I A ) . Note (a) suppression of t a i l and back f e a t h e r i n g and a l s o the uniformly short secondary f l i g h t f e a t h e r s at four weeks (b) pointed t i p s of secondary f l i g h t feathers and (c) r e l a t i v e f u l l n e s s of f e a t h e r i n g at e i g h t weeks of age.  PLATE X I I Type 2 - Female #260 (see P l a t e I X ) . T y p i c a l female development noted a t s i x and eight weeks.  F E A T H E R  D E V E L O P M E N T I N  R H O D E i  T H E  I S L A N D  R E D  A N D N E W  H A M P S H I R E C R O S S  P L A T E S  X I I I I N C L  US  T 0 I V E  X V I I I  PIATE X I I I  The f a m i l y of Type 2 New Hampshire dam #J64-801, showing extreme v a r i a t i o n i n i t s feather development as noted above. Note lower row of b i r d s i n P l a t e s X I I I b and c are females i n the f o l l o w i n g order l e f t to r i g h t : #267, #265, #268 and #261. Males i n X H I b i n the same order are #264, #262, #263 and #266, while i n X I I I c are #263, #264 and #262. (#266 dead a t eight weeks of age.) S i r e : Type EFBB RIR Male #J66-833.  PLATE XIV Feather development of Female #257 - Type EFFF  PIATE XV Feather development of Female #268 - Type FFMT P l a t e XVa - 10 days of age  Note that t h i s female shows the f e a t h e r i n g phenotype normally associated w i t h the presence of the s e x - l i n k e d l a t e - f e a t h e r i n g gene i n s p i t e of the f a c t that i t s s i r e was homozygous f o r the e a r l y - f e a t h e r i n g gene. In t h i s case i t would appear that the r e t a r d a t i o n of feather development must have a r i s e n from the genetic f a c t o r s presumably associated with the bareback c h a r a c t e r i s t i c of the s i r e . Feather development i n t h i s b i r d was i d e n t i c a l t o that of Male #264 (see P l a t e XVI). I n t h i s l a t t e r case, however, such development could normally be assumed t o have been caused by the presence of the l a t e - f e a t h e r i n g gene i n h e r i t e d from the slow-feathering Type 2 New Hampshire dam.  PIATE XVI Feather development of Male  #264  - Type FFMT  P l a t e XVTa - 4 weeks of age  T y p i c a l Type FFMT (E2) f e a t h e r i n g commonly found i n New Hampshires. For 10-day development see P l a t e XVa. Note comparative f u l l n e s s of f e a t h e r i n g a t eight weeks of age i n s p i t e of presumed presence of the l a t e - f e a t h e r i n g gene i n h e r i t e d from the dam. Note, t o o , that by four weeks of age the uniformly short secondaries are almost normal i n l e n g t h although e x h i b i t the aberrant t i p formation a s s o c i a t e d with i n h i b i t i o n of development of feathering.  PIATE XVII Feather development of Male #266 - Type FFST  P l a t e XVTIa - 10 days of age  Note that t h i s male e x h i b i t s r e t a r d a t i o n of feather development of a more extreme nature than #264 ( P l a t e XVI) yet of an appreciably l e s s severe degree than #263 (Plate XVIII). I n h i b i t o r y action i n t h i s case i s not only shown i n the aberrant t i p formation of the secondaries but a l s o can be observed to have a f f e c t e d development of the primary f l i g h t r f e a t h e r s i n a s i m i l a r manner. Note r a p i d i t y of feather development between four and s i x weeks of age. By t h i s l a t t e r age t h i s type resembles c l o s e l y Type FFMT i n s p i t e of the very appreciable d i f f e r e n c e e x h i b i t e d by these two types a t four weeks of age. By s i x weeks, however, Type 2 f e a t h e r i n g s t i l l shows extreme r e t a r d a t i o n ( P l a t e XVIIIc) and even a t eight weeks i s t a i l l e s s , r e l a t i v e l y bare on the wingbows & back, and s t i l l e x h i b i t s short secondary f l i g h t f e a t h e r s (Plate XVTIId).  PLATE X V I I I F e a t h e r development  o f M a l e #263 - Type 2  PIATE XVIIIA  Hampbar Male #390 a t eight weeks of age showing the t y p i c a l Type FFMT (22) f e a t h e r i n g commonly found i n Orpingtons and New Hampshires. Note the looseness and f l u f f i n e s s of t h i s type of f e a t h e r i n g compared to that found i n the Rhode Island Red. Note, too, t h a t t h i s b i r d i s not e a r l y f e a t h e r i n g but, nevertheless, i s f u l l - f e a t h e r e d a t 8 weeks.  F E A T H E R  D E V E L O P M E N T I N  RHODE  THE  I S L A N D  RED  AND WHITE  L E G H O R N  CROSS  P L A T E S  X I X  T 0  INC LU S IYE  X X I I I  PLATE XIX  Male showing Type E l (EFFE) f e a t h e r i n g as observed i n Leghorns homozygous f o r the s e x - l i n k e d e a r l y - f e a t h e r i n g gene & the autosomal normal-feathering gene of the m u l t i p l e a l l e l i c s e r i e s . Note that the t a i l development at four weeks i s not c l e a r l y shown i n the photograph as the b i r d haa i t s t a i l drawn i n c l o s e l y to the body at the time.  PLATS XX  PIATE XXI T y p e E3  feathering.  PIATE XXII Type E4 f e a t h e r i n g . P l a t e XXIIa - £ days of age  Note (a) e a r l y d i f f e r e n t i a t i o n from Type E l , (b) s i m i l a r i t y t o Type E2 up t o ten days of age, a f t e r which period genetic d i f f e r e n c e s r e f l e c t themselves i n feather development, (c) retarded development & abnormal t i p formation of secondary f l i g h t feathers r e v e a l i n g the presence of i n h i b i t o r y f a c t o r s i n the b i r d ' s genetic c o n s t i t u t i o n . See P l a t e XXb f o r c h a r a c t e r i s t i c development of the t a i l which makes i t s appearance later. r  PIATE T y p e E5  XXIII  feathering.  ADULT F E A T H E R  D E V E L O P M E N T I N  RHODE  I S L A N D  RED  AND NEW  H A M P S H I R E  C O C K E R E L S  P L A T E S  X X I V  T 0  I N C L U S I V E  XXV  PLATE  MM  P l a t e XXIVa - 31 weeks of age - Male J266-374  P l a t e s SSIV and XXV show the c o r r e l a t i o n between the "pin-feathery" aspect of r e tarded hackle development and delayed growth of the t a i l feathers i n the adult plumage of some Rhode I s l a n d Red and New Hampshire c o c k e r e l s . P l a t e s XXIVa and XXVa r e s p e c t i v e l y show normal development i n these two breeds. P l a t e s XXIVb and XXIVc show progressive stages of development i n the Rhode I s l a n d Reds a t 25 and 31 weeks r e s p e c t i v e l y .  PLATE XXV  

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