Science, Irving K. Barber Faculty of (Okanagan)
Non UBC
Biology, Department of (Okanagan)
Management, Faculty of (Okanagan)
DSpace
Animals 14 (6): 861 (2024)
Maciel, Fabiane de Fátima
Gates, Richard Stephen
Tinôco, Ilda de Fátima Ferreira
Pelletier, Nathan
Ibarburu-Blanc, Maro A.
Renato, Natalia dos Santos
Sousa, Fernanda Campos de
Andrade, Rafaella Resende
Silva, Guilherme Moreira de Melo
Becciolini, Valentina
Brazil stands as one of the world’s leading producers of animal protein, ranking sixth in global egg production. However, estimated growth in production demand, along with environmental impacts, represents a potential threat to the sustainability of the food system. Methods for assessing and quantifying the environmental impacts generated by Brazilian egg production remain scarce, lacking current reports on comparative effects or guiding standards. The objective of this study was to conduct a life cycle assessment from cradle to farm gate, adhering to ISO 14040 and 14044 standards, for the battery cage egg production systems and associated products in Brazil, with the aim of supporting and promoting sustainability improvements in the Brazilian egg industry. The entire life cycle modeling and process sustainability analysis were executed using the openLCA software, integrated with the Ecoinvent database. Emissions related to egg production yielded results of 65.06 kg SO2 eq., 27.74 kg N eq., 3086.71 kg CO2 eq., 75,152.66 CTUe, 2.75 × 10−5 CFC-11 eq., and 10,044.68 kg MJ eq. per ton of eggs produced. These findings can serve as comparative benchmarks for future studies and for analyzing data across different egg production systems in Brazil.
Citation: Maciel, F.d.F.; Gates, R.S.;Tinôco, I.d.F.F.; Pelletier, N.;Ibarburu-Blanc, M.A.; Renato, N.d.S.;Sousa, F.C.d.; Andrade, R.R.; Silva,G.M.d.M.; Becciolini, V.Environmental Impacts of theBrazilian Egg Industry: Life CycleAssessment of the Battery CageProduction System. Animals 2024, 14,861. https://doi.org/10.3390/ani14060861Academic Editor: Jiakui LiReceived: 1 February 2024Revised: 27 February 2024Accepted: 5 March 2024Published: 11 March 2024Copyright: © 2024 by the authors.Licensee MDPI, Basel, Switzerland.This article is an open access articledistributed under the terms andconditions of the Creative CommonsAttribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).animalsArticleEnvironmental Impacts of the Brazilian Egg Industry: Life CycleAssessment of the Battery Cage Production SystemFabiane de Fátima Maciel 1,* , Richard Stephen Gates 2,† , Ilda de Fátima Ferreira Tinôco 1 , Nathan Pelletier 3 ,Maro A. Ibarburu-Blanc 4 , Natalia dos Santos Renato 1 , Fernanda Campos de Sousa 1 ,Rafaella Resende Andrade 5 , Guilherme Moreira de Melo Silva 6 and Valentina Becciolini 71 Department of Agricultural Engineering, Universidade Federal de Viçosa, Viçosa 36570-900, MG, Brazil;iftinoco@ufv.br (I.d.F.F.T.); natalia.renato@ufv.br (N.d.S.R.); fernanda.sousa@ufv.br (F.C.d.S.)2 Departments of Agricultural and Biosystems Engineering and Animal Science, Iowa State University (ISU),Ames, IA 50011, USA; rsgates@iastate.edu3 Faculties of Science (Biology) and Management, University of British Columbia, Okanagan Campus,Kelowna, BC V1V 1V7, Canada; nathan.pelletier@ubc.ca4 Egg Industry Center, Iowa State University (ISU), Ames, IA 50011, USA; maro@iastate.edu5 Department of Biosystems Engineering, College of Agronomy, Federal University of Goiás,Goiânia 74690-900, GO, Brazil6 Grupo Mantiqueira Brasil, Primavera do Leste 78850-000, MT, Brazil;guilhermemoreira@mantiqueirabrasil.com.br7 Department of Agriculture, Food, Environment and Forestry, University of Florence, 50145 Florence, Italy;valentina.becciolini@unifi.it* Correspondence: fabiane.maciel@ufv.br; Tel.: +55-31-98721-0842† Deceased.Simple Summary: Promoting sustainability in food production has become essential to meet marketdemands, mainly due to its tendency to expand throughout the world. Life cycle assessment is amethodology recognized for providing quantitative information on the environmental impacts causedthroughout the production cycle in different categories. The objective of this study was to carry out anassessment of the life cycle, from the cradle to the farm gate, following ISO 14040 and 14044 standards,for the battery cage egg production systems and associated products in Brazil. The results showedthat interventions focused on feed formulation, manure management, and the welfare of laying hensplay a fundamental role in promoting sustainability in battery cage egg production systems.Abstract: Brazil stands as one of the world’s leading producers of animal protein, ranking sixth inglobal egg production. However, estimated growth in production demand, along with environmentalimpacts, represents a potential threat to the sustainability of the food system. Methods for assessingand quantifying the environmental impacts generated by Brazilian egg production remain scarce,lacking current reports on comparative effects or guiding standards. The objective of this study was toconduct a life cycle assessment from cradle to farm gate, adhering to ISO 14040 and 14044 standards,for the battery cage egg production systems and associated products in Brazil, with the aim ofsupporting and promoting sustainability improvements in the Brazilian egg industry. The entirelife cycle modeling and process sustainability analysis were executed using the openLCA software,integrated with the Ecoinvent database. Emissions related to egg production yielded results of65.06 kg SO2 eq., 27.74 kg N eq., 3086.71 kg CO2 eq., 75,152.66 CTUe, 2.75 × 10−5 CFC-11 eq., and10,044.68 kg MJ eq. per ton of eggs produced. These findings can serve as comparative benchmarksfor future studies and for analyzing data across different egg production systems in Brazil.Keywords: agricultural sector; egg production; intensive system; sustainability; LCA; LCI; LCIAAnimals 2024, 14, 861. https://doi.org/10.3390/ani14060861 https://www.mdpi.com/journal/animalsAnimals 2024, 14, 861 2 of 251. IntroductionBrazil is recognized as a significant player in the global animal protein market, holdingprominent positions in various categories. In 2022, the country was the second-largestproducer of both beef and chicken, leading the way in exporting these two products.Moreover, Brazil stands as the fourth-largest pork producer and holds the fourth positionin the global pork export market [1,2]. Additionally, Brazil has claimed the sixth spot inegg production, with a staggering output exceeding 52.06 billion units [3]. According tothe ABPA (Brazilian Animal Protein Association) [1], 99.6% of Brazilian egg production isdestined for the national market, and only 0.44% is destined for the international market,with expectations of significant growth in egg exports in the coming years. Despite theshare of the export market, where 57% consists of fresh eggs and 43% of processed ones,Brazilian eggs have found their way into families’ households in 83 consumer countriesaround the world. These nations are distributed across different regions, with the MiddleEast accounting for the largest share at 64.41% of the import market, followed by theAmericas (16.42%), Asia (14.49%), Africa (1.42%), Oceania (1.37%), the European Union(1.16%), and Europe Extra-EU (0.46%) [1,3].The anticipated increase in demand for animal-derived products, along with the corre-sponding environmental consequences, represents a potential threat to the sustainability ofthe entire food system. This encompasses production, processing, and distribution, collec-tively responsible for generating 21% to 37% of global greenhouse gas (GHG) emissions [4].As reported by the Food and Agriculture Organization (FAO) [5] and the IntergovernmentalPanel on Climate Change (IPCC) [6], global emissions from these systems witnessed anapproximate 16% increase between 1990 and 2019, with expectations of continued growth.Therefore, it becomes imperative to identify and disseminate best practices in sustainabilitymanagement with the aim of achieving reductions in production-related impacts.Sustainability in livestock production is related to various critical aspects such as foodsecurity, public health, worker safety, biodiversity loss, economic accessibility, and animalwelfare [7]. As a result, the challenge within the animal production system, especially inactivities related to the egg industry, lies in a delicate balance among all these environmentalfactors while simultaneously meeting the existing production demands [7,8].The prevailing egg production system in Brazil is the battery cage system, imple-mented in open or semi-open barns, comprising around 95% of the national egg production.Within this production system, two main types of installations are prominent, distin-guished by the arrangement of the cages: the pyramid or Californian model and thevertical model [9]. On the other hand, extensive or alternative systems, including cage-free,free-range, organic, and “colonial” (traditional), collectively represent an estimated 5% ofBrazilian production. However, it is noteworthy that statistical production authorities donot effectively quantify these alternative systems [9,10]. These systems represent distinctcharacteristics inherent to housing design and management, including feeding (particularlyin the case of organic systems) and the overall cost of egg production [11].In Brazil, there is a shortage of methods to assess and quantify the environmentalimpacts associated with egg production. Currently, there are no existing records forcomparative effects or guidelines for enhancing production practices. As a result, theadoption of new production systems is being implemented at a slow pace due to thepotential impact on the product’s pricing and its accessibility to consumers [12].Life Cycle Assessment (LCA) is regarded as a leading tool for evaluating the environ-mental performance of a production system [13]. LCA is an internationally standardizedmethod, and its application is governed by ISO14040–14044 standards [14,15]. LCA servesas a method to assess the potential environmental and human health impacts of productsand services throughout their life cycle, starting from raw material extraction and coveringall stages of production, transportation, manufacturing, use, and end-of-life treatment [16].It is important to emphasize that LCA applications enable the estimation of potential en-vironmental impacts over the life cycle of a system, quantifying, within current scientificand data limitations, the likely emissions produced and resources consumed. Furthermore,Animals 2024, 14, 861 3 of 25LCA identifies “hotspots” within the supply chain that may be prioritized for sustainabilityimprovement efforts [17]. Therefore, the environmental impacts calculated through LCAshould not be interpreted as absolute values but rather as relative within the scope of thestudy [18].As a calculation tool, the open-source LCA software OpenLCA, version 2.0 [19], wasused in conjunction with the Ecoinvent database, version 3.9.1. These databases incorporatea set of flows, including product flows, elementary flows (extracted from the environmentwithout prior human transformation), and waste flows [20]. Processes are then establishedbased on these flows, which are listed and quantified as inputs/outputs (through inventorydata), consequently allowing the creation of a comprehensive product system. By defininga product system, it is possible to calculate the impacts generated using the desired impactassessment method [21].LCA has been extensively applied to various egg production systems globally, includ-ing countries such as the Czech Republic [22], Canada [23–26], Mexico [27], the USA [28],Spain [29], the UK [30,31], Australia [32], the Netherlands [33], and Sweden [34], amongothers. Across these studies, there is a consistent identification of feed production andmanure management practices as the principal contributors to the environmental im-pacts within the egg production chain. However, these findings collectively offer valu-able insights and opportunities for interventions aimed at enhancing the sustainability ofegg production.In order to support and promote sustainability improvements in the Brazilian eggindustry, this study aims to conduct an LCA from cradle to farm gate, following ISO 14044guidelines [15], for the battery cage-based egg production system and related products.Specifically, this study seeks to quantify the use of resources and emissions attributable tothe evaluated production system, including specific production inputs. It aims to identifymitigation potential and specific interventions to enhance resource use efficiency and reduceemissions from Brazilian egg production. In the future, the baseline model developed inthis study could be utilized to support additional analyses and comparisons investigatingstrategies for environmental impact mitigation. It could also contribute to productionimprovement plans, such as increasing efficiency and resource use, implementing newtechnologies, incorporating renewable energy, optimizing natural resources, and valorizingmanure, among other strategies [35–38].2. Material and Methods2.1. Scope of the Study2.1.1. Brazilian Egg Production ChainThis study utilized a database sourced from a farm located in the Brazilian Midwest,a region characterized by a predominantly semi-humid tropical climate, describing twowell-defined seasons—dry winter and hot, rainy summer [39]. The farm is organized intofive sectors: a feed mill, pullet barns, laying barns, a sorting and dispatch area, and acomposting area designated for manure management.In the upstream segment of the egg production chain, inputs are primarily sourcedfrom the production of crops such as corn and soybeans, along with the production ofone-day-old chicks [40]. These inputs are directed into the farm and specifically allocatedto the feed mill and pullet barns, where they play an important role in the productionof pullets.Within the farm, a feed mill is dedicated to the production of mashed feed, and the en-tire manufacturing process is automated—from the measurement of inputs to the dispatchof the feed. The types of feeds produced vary in accordance with the production phases oflaying hens and their specific nutritional requirements at each stage [41]. The eleven pulletbarns, along with the forty-eight laying barns, are structured in the conventional system ofvertically arranged cage pullet. From 1 to 14 days of age, chicks are accommodated in cageswith dimensions of 0.74 × 0.58 m, hosting an average of 67 chicks per cage (64 cm2 perchick). Commencing on the 15th day of age, a distribution process is initiated, transferringAnimals 2024, 14, 861 4 of 25the chicks to pullet production cages with dimensions of 0.70 × 0.80 m. These cages housean average of 17 pullets each (330 cm2 per pullet), and they remain in the pullet barns untilthe 17th week of age. After this period, there is a transfer process from the pullet barnsto the laying barns, where the laying hens will stay for 88 weeks. These laying barns areequipped with cages of the same dimensions but with an average of 13 laying hens percage (430 cm2 per laying hen). At the conclusion of the production cycle, after 88 weeks,spent hens are subsequently evaluated and sold to processing plants.The eggs from the laying facilities are transferred to the grading sector through anexternal conveyor system. In this sector, the eggs undergo anomaly detection and arecategorized based on size and quality as type A, B, or C eggs. Type A eggs, which are inperfect condition for sale, are packaged and sent to the dispatch sector. Eggs with smallcracks, categorized as type B, are packaged and sent to another unit for the production ofliquid eggs. The egg-breaking sector is responsible for producing whole liquid eggs, whichare stored and frozen in 18-L buckets, known as industry eggs—type C. All eggs go througha series of hygiene processes before their classification, including washing, enhanced withmineral oil, and are later directed to pack and dispatch or for egg-breaking facilities.The removal of manure from the pullet and laying barns occurs daily through auto-mated conveyors, depositing the collected manure into external containers. These contain-ers are then transported by truck and unloaded in the composting area, along with all theorganic manure generated in the unit. Mortalities experience a dehydration process infurnaces and are also deposited in the composting area. It is worth noting that the twelvecomposting barns store 99% of bird manure and only 1% of other residues. Consequently,the manure undergoes a biotechnological process of organic matter decomposition undercontrolled aerobic conditions, and to enhance the process, low-moisture materials such aswood chips are introduced, resulting in the co-product organic compost. This compost isthen sold to local producers in the region. Figure 1 illustrates the Brazilian egg productionchain in a battery cage system.Animals 2024, 14, x FOR PEER REVIEW 5 of 27 Figure 1. Egg production chain of Brazilian eggs in a battery cage production system. Source: The authors. 2.1.2. System Boundaries The system boundaries for this study comprise all pertinent flows of materials, energy, and emissions in all considered processes, in accordance with ISO 14044 guidelines [15], ranging from cradle to farm gate. This includes all processes related to feed production (inputs, energy, and water); the production of pullets and layers of hens (chicks, feed, energy, water, and manure management); as well as all processes associated with egg grading and processing (eggs, energy, packaging, and water). The internal transportation of material flows between the stages of the supply chain is also considered. Nevertheless, it is important to note that the transportation of eggs and derivatives to retail is not considered in this study, as it occurs beyond the farm gate and falls outside the defined system boundaries. The processing of chickens for human consumption is also excluded as it is outside the system’s boundaries. Regarding the production of organic compost, despite occurring within the farm, it is treated as a co-product derived from the reuse of manure, aligning with the criteria outlined by ISO 14044 [15], which incorporates co-product allocation criteria based on products or residues classified as reusable. In this way, the valorization of spent hens, which are no longer discarded in the environment and are now used for consumption, and the production of organic compost that directs and reuses manure as a source of organic fertilizers are both regarded as allocation factors in evaluating these two co-products. Figure 2 illustrates the system boundaries for an LCA of Brazilian egg production in a battery cage system. Figure 1. Egg production chain of Brazilian eggs in a battery cage production system. Source: Theauthors.2.1.2. System BoundariesThe system boundaries for this study comprise all pertinent flows of materials, energy,and emissions in all considered processes, in accordance with ISO 14044 guidelines [15],ranging from cradle to farm gate. This includes all processes related to feed production(inputs, energy, and water); the production of pullets and layers of hens (chicks, feed,Animals 2024, 14, 861 5 of 25energy, water, and manure management); as well as all processes associated with egggrading and processing (eggs, energy, packaging, and water). The internal transportationof material flows between the stages of the supply chain is also considered. Nevertheless,it is important to note that the transportation of eggs and derivatives to retail is notconsidered in this study, as it occurs beyond the farm gate and falls outside the definedsystem boundaries.The processing of chickens for human consumption is also excluded as it is outsidethe system’s boundaries. Regarding the production of organic compost, despite occurringwithin the farm, it is treated as a co-product derived from the reuse of manure, aligningwith the criteria outlined by ISO 14044 [15], which incorporates co-product allocationcriteria based on products or residues classified as reusable. In this way, the valorizationof spent hens, which are no longer discarded in the environment and are now used forconsumption, and the production of organic compost that directs and reuses manure asa source of organic fertilizers are both regarded as allocation factors in evaluating thesetwo co-products. Figure 2 illustrates the system boundaries for an LCA of Brazilian eggproduction in a battery cage system.Animals 2024, 14, x FOR PEER REVIEW 6 of 27 Figure 2. Limits of the LCA system from cradle to gate of egg production Brazilian eggs in the battery cage production system. Source: Turner et al. [23]; adapted by the authors. 2.1.3. Functional Unit Different functional units (FUs) were employed to describe the results at each stage of the production chain. In feed production, the functional unit was one ton of feed produced; in pullet production, it was 1000 pullets produced; in egg production (layers), the functional unit was one ton of eggs produced; in grading, it was one ton of graded eggs; and in liquid egg production, the functional unit was one ton of liquid eggs produced. All data are applicable to the base year of 2021. 2.1.4. Co-Product Allocation ISO 14044 [15] defines a co-product as one of two or more products originating from the same elementary process. Many agri-food production systems involve multifunctional processes, presenting a common challenge of allocating impacts among co-products [42]. In this study, the egg is considered the main product, with production categorized into Type A eggs (90.31% of production), Type B eggs (9.44%), and Type C eggs, which are marketed in refrigerated buckets (0.25%). Market estimates indicate significant variations in egg prices throughout the year 2021. According to CEPEA [43], the mean price of white eggs remained at approximately BRL127.21 per box with 360 units (equivalent to approximately 21.6 kg of eggs) in the central-west region of Brazil. The co-products considered in this study are the valorization of spent hens and the production of organic compost derived from manure. According to information from the farm, spent hens are sent to processing plants with an average weight of 1.8 kg (ranging from 1.6 to 2 kg) and are commercialized at a rate of BRL 1.5 per kilogram of hen. Once produced, the organic compost is distributed to local producers without any stock of the finished compost. This compost has a high demand, with a market price of BRL 600 per ton. However, it is emphasized that eggs are the primary product of the system and the most significant in terms of nutrition, mass, and economic value [44]. Fig r . i its of the LCA system from cradle to gate of egg production Brazilian eggs in the batterycage production system. Source: Turner et al. [23]; adapted by the authors.2.1.3. Functional UnitDifferent functional units (FUs) were employed to describe the results at each stage ofthe production chain. In feed production, the functional unit was one ton of feed produced;in pullet production, it was 1000 pullets produced; in egg production (layers), the functionalunit was one ton of eggs produced; in grading, it was one ton of graded eggs; and in liquidegg production, the functional unit was one ton of liquid eggs produced. All data areapplicable to the base year of 2021.2.1.4. Co-Product AllocationISO 14044 [15] defines a co-product as one of two or more products originating fromthe same elementary process. Many agri-food production systems involve multifunctionalprocesses, presenting a common challenge of allocating impacts among co-products [42]. InAnimals 2024, 14, 861 6 of 25this study, the egg is considered the main product, with production categorized into TypeA eggs (90.31% of production), Type B eggs (9.44%), and Type C eggs, which are marketedin refrigerated buckets (0.25%). Market estimates indicate significant variations in eggprices throughout the year 2021. According to CEPEA [43], the mean price of white eggsremained at approximately BRL127.21 per box with 360 units (equivalent to approximately21.6 kg of eggs) in the central-west region of Brazil.The co-products considered in this study are the valorization of spent hens and theproduction of organic compost derived from manure. According to information from thefarm, spent hens are sent to processing plants with an average weight of 1.8 kg (rangingfrom 1.6 to 2 kg) and are commercialized at a rate of BRL 1.5 per kilogram of hen. Onceproduced, the organic compost is distributed to local producers without any stock of thefinished compost. This compost has a high demand, with a market price of BRL 600 perton. However, it is emphasized that eggs are the primary product of the system and themost significant in terms of nutrition, mass, and economic value [44].2.1.5. Cutting and Exclusion CriteriaIn this study, the incubation of chicks was not considered, as the acquisition of chicks isoutsourced by the farm and is outside the defined system limits. Previous studies proposedby Pelletier et al. [28], Pelletier [24,25], and Turner et al. [23] suggest that, although necessaryfor a comprehensive LCA, breeding batches and incubation facilities make relatively trivialcontributions to the overall life cycle impacts in the egg industry.Modeling for medication use, including antibiotics, cleaning products, and entericfermentation for hens, as well as the maintenance of infrastructure, such as machinery andfarm buildings, was excluded from the evaluation.In this assessment, a single average value for egg mass (60 g) was considered, followingthe farm’s guidelines, rather than accounting for a distribution of sizes of produced eggs,as suggested by Ibarburu et al. [45].In the present study, a single egg-producing farm was considered within the batterycage production system. However, obtaining foreground data remains a challenge inthe country. It is remarkable that the evaluated farm has a high production potential,pioneeringly representing the domestic market by producing over 1.2 billion units of eggsin 2021 and experiencing growing demand in the international market.2.2. Life Cycle Inventory—LCI2.2.1. Data Sources and AssumptionsThe foreground system data are those directly collected from producers within thesupply chain under study, incorporating inputs and outputs of products, as well as emis-sions related to the various stages of the production chain [24]. The foreground systemdata for this study were collected jointly with the farm through answers to questionnairesand meetings with the responsible sectors involved in feed production, pullet and layinghen production, egg grading, liquid egg production, and manure management, ensuringthat the data source remained confidential throughout the process.Background system data are obtained through information derived from an LCIdatabase, with support for various types of sustainability assessments that constitute one ofthe most critical steps in the LCA process [46]. In this study, production and supply modelsfor food inputs, water, energy, packaging, and transportation means were utilized, sourcedfrom the EcoInvent database [47,48], and modified whenever possible to better align withBrazilian conditions.Modeling N, P and CH4 Emissions from ManureThe values related to volatile solids excreted were considered in accordance with theIPCC [49,50], along with the annual quantity of excreta produced by the farm. To calculatenitrogen (N) excretion, a mass balance was performed based on feed consumption, jointlywith the assessment proposed by ASAE [51] and França [52]. Phosphorus (P) excretionAnimals 2024, 14, 861 7 of 25was also determined through a mass balance based on feed consumption. For P lossestimates, a value of 3.48% was assumed, representing the expected average losses in Brazil,in accordance with the average rates found by Rittmann et al., Piovesan, and Peles [53–55].The percentages of N and P in the feed for pullets and laying hens were calculatedbased on the nutritional levels specified in the composition of both formulations, as pro-vided by the farm, with the percentage of 18.5% crude protein (CP) and 0.6% phosphorus(P) for the pullet feed, and 16.7% CP and 0.52% P for the laying hen feed.The estimates of nitrogen emissions applied to the soil were calculated by subtractingthe N emitted during manure management from the nitrogen excreted. The values fornitrous oxide (N2O), nitrate (NO3), nitric oxide (NOx), ammonia (NH3), and methane(CH4) were computed using Tier 1 and 2 equations from the IPCC guidelines [49,50]. As aresult, the estimated values are 4.85 kg N2O, 68.45 kg NO3, 48.92 kg NH3, 12.00 kg NOx,27.01 kg CH4, and 3.56 kg P2O5 per 1000 units of caged pullets produced; and 1.99 kg N2O,31.91 kg NO3, 22.42 kg NH3, 5.50 kg NOx, 3.18 kg CH4, and 1.21 kg P2O5 per ton of eggsproduced. Tables S1 and S2 in Supplementary S1—Supplementary Information provide acomprehensive description of the considered values.Modeling of Food InputsThe feed compositions considered comprise a total of ten formulations, with five feedsdesignated for the pullet phase, named Pre-Starter, Starter, Grower, Maturity, and Pre-Laying; and five feeds designated for the laying phase, named Start, Peak, Laying 1, Laying2, and Laying 3. The Pre-Starter feed, when used, starts on the first day of the chick’s lifeand continues until the second week, concluding at 14 days. In most cases, the Starter feedis adopted from the first day until the sixth week, concluding at 42 days. The Grower feed isused from the 7th to the 10th week, concluding at 70 days. The Maturity feed is used fromthe 11th to the 15th week, ending at 105 days, and can be used up to the production phase,reaching 17 weeks. The Pre-Laying feed, when used, starts in the 16th week until the startof production in the 17th week, concluding at 119 days. For the feeds destined for the layingphase, the Start feed begins in the 18th week and continues until the 30th week, concludingat 210 days. The Peak feed, from the 31st week to the 50th week, concluded at 350 days.Laying 1 feeds from the 51st week to the 70th week, concluding at 490 days. The Laying 2feeds from the 71st week to the 90th week, concluding at 630 days. Finally, the Laying 3feeds from the 91st week until the disposal of the laying hen, which can vary from 770 daysto 875 days when the molting process occurs. These feed compositions are estimated/usedby the farm as needed. The compositions of the feeds for the pullet and laying houses canbe found in Tables S3 and S4 in Supplementary S2—Supplementary Information.After analyzing the quantity of all compositions, a unified formulation was consideredfor both pullet and laying phases, as considered in studies proposed by Pelletier et al. [28],Pelletier [24,25], and Turner et al. [23]. In all feed compositions, corn and soy (derivatives)emerge as the predominant food ingredients. For this assessment, ingredients constitutingless than 1% of the composition were not considered. The inventory models for feedproduction were derived from the EcoInvent database, in collaboration with the Sustellplatform, which integrates major LCA agro-food databases such as Agri-footprint andGFLI [56–58].2.2.2. Assessment of Data Quality and UncertaintyISO 14044 [15] requires an assessment of data quality to ensure that low-quality datado not adversely impact the results. These assessments can contribute to improvements indata quality but also help to identify key variables for sensitivity analyses [24].Data quality was evaluated according to each flow across all foreground processesusing the standard Ecoinvent pedigree matrix, as outlined by Ciroth et al. [59], describedin Table S5 in Supplementary S3—Supplementary Information. The assessment of dataquality for flows in all processes was evaluated based on reliability, integrity, and temporal,geographical, and technological correlation within the modeling context. A scoring scaleAnimals 2024, 14, 861 8 of 25from 1 to 5 was employed in this system, with 1 indicating the highest quality data and5 indicating the lowest quality data. The specific assignments for each process are presentedin Table S6 in Supplementary S4—Supplementary Information [21].Pelletier [24,25] categorizes uncertainties in LCA studies into three types: inven-tory data uncertainty, characterization model uncertainty, and LCI model uncertainty.Bamber et al. [60] concluded in their studies that less than 20% of LCA studies publishedbetween 2014 and 2018 reported any form of uncertainty analysis. While inventory datauncertainty is most frequently reported (82% of the studies), other sources of uncertaintyare considered equally important. Monte Carlo analysis emerged as the most popularmethod, utilized by 61% of publications to propagate uncertainty results, regardless of thetype of LCA. Using the OpenLCA software, both data quality and uncertainty values werecalculated from matrices and Monte Carlo simulations [19,21].2.3. Life Cycle Impact Assessment—LCIA2.3.1. Impact Assessment Method and IndicatorsAccording to the ISO 14044 guidelines [15], the LCIA phase should consider a compre-hensive set of impact categories related to the product system under study. To determine aconsensus set of impact categories most relevant to egg production systems, a review ofLCA studies on egg production was conducted, as outlined by Maciel et al. [17].Among the assessed impact categories, there was significant diversity in the impactcategories considered in LCA studies for eggs across different countries. The analysisof 20 sources covering 10 different countries, including the Czech Republic, Canada, theUnited Kingdom, Serbia, the USA, Italy, Sweden, Mexico, the Netherlands, and Spain,identified a total of 25 different impact categories. Emissions related to global warmingpotential (CO2 eq.) were unanimously considered in all studies, followed by acidification(SO2 eq.), eutrophication (N eq.), ecotoxicity (CTUe), ozone depletion (CFC eq.), andcumulative energy demand fossil (MJ eq.), ranging from 65% to 55% of the studies. Otherrelated impacts were not considered, as they remained below 50% of the analyzed studiesand did not align with the reality of egg production considered in Brazil. Therefore, theimpact categories to be evaluated include acidification, eutrophication, global warmingpotential (GWP), ecotoxicity, ozone depletion, and cumulative fossil energy demand (CED),as shown in Table 1.Table 1. Selected impact categories for the assessment of environmental impacts in egg productionand their characterization factor units.Impact Categories Characterization Factor UnitAcidification kg SO2 eq.Eutrophication kg N eq.Global warming potential (GWP) kg CO2 eq.Ecotoxicity CTUe (unidades tóxicas comparativas)Ozone depletion kg CFC-11 eq.Cumulative Energy Demand (CED) fossil MJ eq.2.3.2. Comparisons with Other StudiesLCIA Egg ProductionInternational studies report the environmental performance of battery cage egg pro-duction; however, direct comparisons between studies are uncertain due to frequent differ-ences in the considered modeling. Nevertheless, it is interesting to consider and comparethe impacts reported by various studies, including Guillaume et al. [22], Turner et al. [38],Estrada-González et al. [27], Abín et al. [29], Pelletier [24,25], Pelletier et al. [28], Leinonenet al. [30,31], Wiedemann and McGahan [32], Mollenhorst et al. [33], Cederberg et al. [34],and Vergé et al. [26], to the findings of the current study.Although there are currently no publications on LCA for Brazilian egg production, a se-ries of LCAs have been conducted for agricultural industries in response to the growing de-Animals 2024, 14, 861 9 of 25mand for information on food products and supply chains [32]. The authors Dick et al. [61],Cardoso et al. [62], Willers et al. [63], Dick et al. [64], Leis et al. [65], Carvalho et al. [66],Barros et al. [67], Maciel et al. [68], Silva et al. [69], Lima et al. [70], Alves et al. [71],Cherubini et al. [72], and Alvarenga et al. [73] describe Brazilian LCA, considering keyagro-industrial products such as beef cattle, dairy cattle, broiler chickens, pork, and broilerfeed, across their various production systems.More specific studies get into the assessment of product quality in special confinementsystems, reflecting the trend toward qualitative consumption of products, as indicatedby Morais et al. [74]. In their study, they concluded values of 5.03, 4.77, and 8.89 kg ofCO2 eq./kg of live weight gain in confinement for premium, super-premium Angus, andsuper-premium Wagyu meats, respectively.3. Results3.1. Life Cycle Inventory ResultsThe LCI data are presented in Tables 2–7, corresponding to the functional unit of eachproduction.Table 2. Percentage of feed composition for pullets and laying hens per ton of feed produced.Ingredients % Feed Pullets % Feed Laying HansMaize 65.28 62.19DDGs _ 8.00Limestone 1.83 10.11Methionine 0.29 0.19Meat and Bone Meal 4.01 2.06Salt 0.35 0.20Soybean meal 20.31 14.87Soybean hull 7.25 1.30Vegetable oil _ 0.11Vitamins and minerals 0.34 0.65Soy oil _ 0.32Others 0.34 _Table 3. LCI data for producing 1000 units of broiler chickens in battery cage systems.2021 Average Pullets ProductionInputsChicks (units) a 1025Mass/Chicks (g) a 35Transportation (t*km) a 37.10Feed (tons) a 5.48Transportation (t*km) a 7.31Water (m3) ab 14.38Electricity (kWh) a 227.32Diesel (L) ab 80.88OutputsPullets (unit) 1000Mass (tons) a 1.21Manure (tons) ab 4.27Transportation (t*km) a 5.71N excreted (kg) b 162.06P excreted (kg) b 33.29Mortality rate (%) a 2.35Transportation (t*km) a 0.02a Based on primary research data; b Data estimated, modeled, or taken from the literature; ab Total primary dataand estimate (by sector).Animals 2024, 14, 861 10 of 25Table 4. LCI data for producing one ton of eggs in battery cage production systems.2021 Average Egg ProductionInputsPullets (unit) a 36.27Distance (t*km) a 11.54Feed (tons)a 2.16Distance (t*km) a 2.89Water (m3) ab 3.07Electricity (kWh) a 102.51Diesel (L) ab 7.63OutputsEggs (tons) 1Spent hens (kg) a 51.50Mass/spent hens (kg/hen) a 1.80Distance (t*km) a 77.25Manure (tons) ab 2.06Distance (t*km) a 2.75N excreted (kg) b 57.80P excreted (kg) b 11.36Mortality rate (%) a 13.04%Distance (t*km) a 1.34a Based on primary research data; b Data estimated, modeled, or taken from the literature; ab Total primary dataand estimate (by sector).Table 5. LCI data for producing one ton of graded eggs.Classified Eggs in 2021InputsEggs (kg) a 1002.56Water (m3) ab 4.18Electricity (kWh) a 28.82Packaging (kg)Cardboard (kg) a 48.36Plastic film and acrylic (kg) a 34.88OutputsEggs (Type A) (kg) a 900.76Eggs (Type B) (kg) a 94.19Eggs (Type C) (kg) a 2.50Discarded eggs (kg) a 2.56a Based on primary research data; ab Total primary data and estimate (by sector).Table 6. LCI data for producing one ton of processed liquid egg.Production of Liquid Eggs in 2021InputsEggs (kg) a 1299.13Transportation (t*km) a 1295.23Water (m3) a 9.08Electricity (kWh) a 195.71GLP gas (m3) a 9.62Packaging (kg) 1.89Cardboard (kg)a 1.02Plastic Film and Acrylic (kg) a 0.87OutputsWhole Liquid Eggs (kg) a 1000Eggshells (kg) a 138.84Discarded Eggs (kg) a 52.63a Based on primary research data.Animals 2024, 14, 861 11 of 25Table 7. LCI data for producing one ton of organic compost.Production of Organic Compost in 2021InputsManure ProducedPoultry Manure (kg) ab 2360.94Carcasses and Other Residues (kg) ab 33.09Transportation (t*km) a 28.33Water (m3) ab 0.08Diesel (L) ab 20.90Shredded Eucalyptus—Wood Chips(kg) a 2.78OutputsOrganic Compost (kg) a 1000a Based on primary research data; ab Total primary data and estimate (by sector).The data represent a total of 171,703 tons of feed in 2021.The data represent the production of 2,636,550 pullets in 2021.The data represent a total egg production of 72,698.23 metric tons in the year 2021.The data represent the total production of 65,483.60 metric tons of Grade A eggs,which are packaged and sold; 6847.14 metric tons of Grade B eggs, intended for liquid eggproduction; and 181.63 metric tons of Grade C eggs, which are refrigerated and sold in 18-Lbuckets. All production values refer to the year 2021.The data represent the production of 1953.75 metric tons of liquid egg in the year 2021.The collected data represent the production of 68,156 metric tons of organic compostin the year 2021.3.2. Allocation Results for Co-ProductsTable 8 presents the allocation of co-products, organic compost, and spent hens basedon the production quantity in mass (metric tons) and their respective economic value.Table 8. Co-product allocation and allocation percentage based on mass and economic value.Product Mass Production (ton.) Economic Production(BRL)Percentage MassProduction (%)Percentage EconomicProduction (%)Egg 72,698.23 742,026,471.7 50 94Organic compost 68,156 40,893,600 47 5Spent hens 3744 5,616,000 3 1The mass production percentages of eggs and organic compost are considered similarwhen compared (within a 3% variation) but present relevant economic values. Therefore,the economic allocation method is considered more suitable, resulting in an allocation factorof 94% for egg production, 5% for organic compost production, and 1% for the valuation ofspent hens.3.3. Life Cycle Impact Assessment ResultsAll the results of the LCIA are presented in detail in Tables 9–11, using reference unitsfor each impact category in accordance with the egg production chain.The higher impacts in acidifying emissions and fossil CED observed in the GrowerFeed are contrasted by the Maturity Feed, which displays higher impacts in eutrophication,greenhouse gas emissions, ozone depletion, and ecotoxicity. This disparity between the twofeeds is linked to the increased percentage of corn-based ingredients (1.4%) in the GrowerFeed and soy derivatives (1.8%) in the composition of the Mature Feed.Animals 2024, 14, 861 12 of 25Table 9. LCIA results per ton of feed produced for the pullet phase.Impact Category Pre-Starter Feed Starter Feed Grower Feed Maturity Feed Pre-Laying FeedAcidifyingemissions(kg SO2 eq)4.48 4.51 4.52 4.49 4.37Eutrophyingemissions(kg N eq)6.11 6.02 6.04 6.17 5.75GHG emissions(kg CO2 eq)1285.58 1250.66 1257.31 1303.21 1185.97Ecotoxicity(CTUe) 42,900.81 41,391.65 41,645.30 43,595.72 39,042.66Ozone depletion(kg CFC-11 eq) 1.31 × 10−5 1.29 × 10−5 1.29 × 10−5 1.32 × 10−5 1.24 × 10−5CED fossil(MJ eq) 4332.61 4354.86 4364.24 4348.38 4214.02Table 10. LCIA results per ton of feed produced for the laying phase.Impact Category Starter Feed Peak Feed Laying Feed 1 Laying Feed 2 Laying Feed 3Acidifyingemissions(kg SO2 eq)3.93 4.01 4.03 4.04 4.01Eutrophyingemissions(kg N eq)4.73 4.68 4.71 4.64 4.66GHG emissions(kg CO2 eq)922.55 895.66 900.45 874.64 886.68Ecotoxicity(CTUe) 29,169.63 27,897.89 28,045.00 26,964.00 27,534.83Ozone depletion(kg CFC-11 eq) 1.04 × 10−5 1.04 × 10−5 1.04 × 10−5 1.03 × 10−5 1.03 × 10−5CED fossil(MJ eq) 3771.96 3833.92 3854.63 3857.02 3828.50Table 11. LCIA results per ton of feed for pullets and laying hens, per 1000 units of pullets produced,per ton of eggs produced, per ton of graded eggs, and per ton of liquid eggs produced.ImpactCategoryFeed Production(Pullets)Feed Production(Laying Hens)PulletsProductionEggProduction Egg GradingLiquid EggProductionAcidifyingemissions(kg SO2 eq)4.48 4.00 129.46 65.06 65.78 85.30Eutrophyingemissions(kg N eq)6.02 4.68 64.29 27.74 28.26 36.33GHG emissions(kg CO2 eq)1256.54 896.00 8365.25 3086.71 3232.93 4355.12Ecotoxicity(CTUe) 41,714.92 27,922.16 228,568.90 75,152.66 76,676.23 100,286.33Ozonedepletion(kg CFC-11 eq)1.29 × 10−5 1.04 × 10−5 7.17 × 10−5 2.75 × 10−5 3.04 × 10−5 4.33 × 10−5CED fossil(kg MJ eq) 4322.82 3829.20 24,117.43 10,044.68 13,541.11 18,436.53Animals 2024, 14, 861 13 of 25The Starter Feed exhibits higher impacts related to eutrophication, greenhouse gasemissions, ozone depletion, and ecotoxicity. On the other hand, Laying Feed 2 showshigher impacts related to acidifying emissions and fossil CED. This variation between theStarter Feed and Laying Feed 2 is attributed to the increase in the percentage of soy-derivedingredients (2.2%) and meat and bone meal (1.7%) in the composition of the Starter Feedand corn (3.1%) in the composition of Laying Feed 2.3.3.1. LCIA Results—Feed ProductionWhen analyzing the LCIA results of one ton of feed produced for pullets, accordingto impact categories, in acidifying emissions, corn accounts for 82.4% and soy for 17.3%;in eutrophying emissions, corn represents 51.5% and soy for 48.4%; in GHG emissions,corn accounts for 33.7% and soy for 66.1%; in ecotoxicity, corn represents 22.2% and soyfor 77.8%; in ozone depletion, corn corresponds to 58% and soy to 41.7%; in fossil CED,corn corresponds to 79% and soy to 20.4% of the generated impacts. Other inputs such asbone meal, limestone, natural resources, and energy account for less than 1% of the impactgenerated in the production of one ton of feed for pullets.When analyzing the LCIA results of one ton of feed produced for laying hens, inacidifying emissions, corn accounts for 87.8% and soy for 11.4%; in eutrophying emissions,corn represents 63.11% and soy for 36.5%; in GHG emissions, corn accounts for 45.05%and soy for 54.4%; in ecotoxicity, corn represents 31.6% and soy 68.2%; in ozone depletion,corn corresponds to 68.7% and soy to 30.4%; in fossil CED, corn corresponds to 85% andsoy represents 13.5% of the generated impacts. Other inputs such as DDG, bone meal,limestone, natural resources, and energy account for less than 1% of the impact generatedin the production of one ton of feed for laying hens.However, for a better understanding and analysis of the impacts generated by feed pro-duction, Figure 3 illustrates the relative percentages of the impacts generated by the feeds.Animals 2024, 14, x FOR PEER REVIEW 15 of 27 Figure 3. Relative percentage of environmental impacts per ton of feed produced for pullets and laying hens. It is evident that the production of feed for laying hens shows a reduction in generated impacts, ranging from 11% to 33% when compared to feed for pullets. 3.3.2. LCIA Results—Pullets Production When analyzing the LCIA results for the production of 1000 units of pullets, it is observed that manure management contributed to impact categories such as acidification, eutrophication, and greenhouse gas emissions, with relatively minor contributions to ecotoxicity, ozone depletion, and fossil CED. However, feed inputs emerge as the primary drivers for ecotoxicity, ozone depletion impacts, and fossil CED. Considering the generated impacts of acidifying emissions, waste management accounts for 81%, while feed production contributes 18.9%. For eutrophying emissions, feed production represents 51.2%, and manure management contributes 48.7%. In greenhouse gas emissions, feed production corresponds to 82.2% and manure management to 17.3%. In terms of ecotoxicity, feed production constitutes 99.9%, with electricity contributing less than 1%. Ozone depletion is primarily driven by feed production at 98.5%, with electricity contributing 1.3%. Fossil CED is dominated by feed production at 98.1%, while electricity accounts for 1.5% of the generated impacts. Other inputs such as transportation, diesel, and water contribute less than 1% to the impact generated in the production of 1000 units of pullets. Figure 4 illustrates the percentage of impacts generated by the production of 1000 units of pullets. 10010010010010010089.2977.7471.3166.9480.4788.580 10 20 30 40 50 60 70 80 90 100SO₂ eq.N eq.CO₂ eq.CTUeCFC-11 eq.MJ eq.Feed production for pullets and laying hens Impact assessment result - Pullets Impact assessment result - LayerFigure 3. Relative percentage of environmental impacts per ton of feed produced for pullets andlaying hens.It is evident that the production of feed for laying hens shows a reduction in generatedimpacts, ranging from 11% to 33% when compared to feed for pullets.3.3.2. I es lts ullets Productionhen analyzing the LCIA results for the production of 1000 units of pullets, it isobserved that anure anagement contributed to impact categories such as acidification,eutrophication, and greenhouse gas emissions, with relatively minor contributions toAnimals 2024, 14, 861 14 of 25ecotoxicity, ozone depletion, and fossil CED. However, feed inputs emerge as the primarydrivers for ecotoxicity, ozone depletion impacts, and fossil CED.Considering the generated impacts of acidifying emissions, waste management ac-counts for 81%, while feed production contributes 18.9%. For eutrophying emissions, feedproduction represents 51.2%, and manure management contributes 48.7%. In greenhousegas emissions, feed production corresponds to 82.2% and manure management to 17.3%.In terms of ecotoxicity, feed production constitutes 99.9%, with electricity contributing lessthan 1%. Ozone depletion is primarily driven by feed production at 98.5%, with electricitycontributing 1.3%. Fossil CED is dominated by feed production at 98.1%, while electricityaccounts for 1.5% of the generated impacts. Other inputs such as transportation, diesel,and water contribute less than 1% to the impact generated in the production of 1000 unitsof pullets. Figure 4 illustrates the percentage of impacts generated by the production of1000 units of pullets.Animals 2024, 14, x FOR PEER REVIEW 16 of 27 Figure 4. Acidifying emissions (kg SO2 eq.), eutrophying emissions (kg N eq.), greenhouse gas emissions (kg CO2 eq.), ecotoxicity (CTUe), ozone depletion (CFC-11 eq.), and fossil CED (MJ eq.) associated with the production of 1000 units of pullets produced. 3.3.3. LCIA Results—Egg Production When analyzing the LCIA results of a ton of eggs produced, it is noted that feed inputs, manure management, and pullet production (which encompass all previously reported impacts) are the main drivers of impacts associated with egg production systems. In impact categories such as ecotoxicity, ozone depletion, and fossil CED, electricity has a greater contribution than manure management due to the nature of electricity production provided by the Brazilian utility [75]. When analyzing the LCIA results, in terms of acidifying emissions, manure management accounts for 73.8%, feed production for laying hens for 13.3%, and pullet production for 12.8%. For eutrophying emissions, manure management contributes 48.6%, feed production for laying hens contributes 36.5%, and pullet production contributes 14.9%. In terms of greenhouse gas emissions, feed production for laying hens corresponds to 62.8%, manure management to 19.3%, and pullet production to 17.4%. In terms of ecotoxicity, feed production for laying hens constitutes 80.4%, and pullet production contributes 19.5%. Ozone depletion is primarily driven by feed production for laying hens at 81.5%, pullet production at 16.7%, and electricity at 1.6%. Fossil CED is dominated by feed production for laying hens at 82.5%, pullet production at 15.4%, and electricity at 1.6% of the generated impacts. Other inputs such as transportation, diesel, and water contribute less than 1% to the impacts generated in the production of one ton of eggs. Figure 5 illustrates the percentage of impacts generated by the production of one ton of eggs. 0%10%20%30%40%50%60%70%80%90%100%SO₂ eq. N eq. CO₂ eq. CTUe CFC-11 eq. MJ eq.LCIA - Pullets ProductionFeed Manure Electricity Transport Diesel WaterFigure 4. Acidifying emissions (kg SO2 eq.), eutrophying emissions (kg N eq.), greenhouse gasemissions (kg CO2 eq.), ecotoxicity (CTUe), ozone depletion (CFC-11 eq.), and fossil CED (MJ eq.)associated with the production of 1000 units of pullets produced.3.3.3. LCIA Results Egg ProductionWhen analyzing the LCIA results of a ton of eggs produced, it is noted that feed inputs,manure management, and pullet production (which encompass all previously reportedimpacts) are the main drivers of impacts associated with egg production systems. In impactcategories such as ecotoxicity, ozone depletion, and fossil CED, electricity has a greatercontribution than manure management due to the nature of electricity production providedby the Brazilian utility [75].When analyzing the LCIA results, in terms of acidifying emissions, manure manage-ment accounts for 73.8%, feed production for laying hens for 13.3%, and pullet productionfor 12.8%. For eutrophying emissions, manure management contributes 48.6%, feed pro-duction for laying hens contributes 36.5%, and pullet production contributes 14.9%. Interms of greenhouse gas emissions, feed production for laying hens corresponds to 62.8%,manure management to 19.3%, and pullet production to 17.4%. In terms of ecotoxicity,feed production for laying hens constitutes 80.4%, and pullet production contributes 19.5%.Ozone depletion is primarily driven by feed production for laying hens at 81.5%, pulletproduction at 16.7%, and electricity at 1.6%. Fossil CED is dominated by feed productionfor laying hens at 82.5%, pullet production at 15.4%, and electricity at 1.6% of the generatedimpacts. Other inputs such as transportation, diesel, and water contribute less than 1%Animals 2024, 14, 861 15 of 25to the impacts generated in the production of one ton of eggs. Figure 5 illustrates thepercentage of impacts generated by the production of one ton of eggs.Animals 2024, 14, x FOR PEER REVIEW 17 of 27 Figure 5. Acidifying emissions (kg SO2 eq.), eutrophying emissions (kg N eq.), greenhouse gas emissions (kg CO2 eq.), ecotoxicity (CTUe), ozone depletion (CFC-11 eq.), and fossil CED (MJ eq.) associated with the production of one ton of eggs. 3.3.4. LCIA Results—Classification Sector When evaluating the results of the classification sector, it is possible to identify that the greatest impacts in all analyzed categories stem from egg production, consequently including the impacts of feed production, pullets, and manure management. Packaging demonstrated a higher contribution to impacts in categories related to GHG emissions (4.1%), ozone depletion (8.9%), and fossil CED (25.3%) from fossil-based plastic packaging (combs, acrylic lids, and plastic film) and cardboard boxes. Other inputs, such as electricity and water, contribute less than 1% to the impact generated in the production of one ton of classified and packaged eggs. Figure 6 illustrates the percentage of impacts generated by the production of one ton of classified eggs. Figure 6. Acidifying emissions (kg SO2 eq.), eutrophying emissions (kg N eq.), greenhouse gas emissions (kg CO2 eq.), ecotoxicity (CTUe), ozone depletion (CFC-11 eq.), and fossil CED (MJ eq.) associated with the classification of one ton of eggs. 0%10%20%30%40%50%60%70%80%90%100%SO₂ eq. N eq. CO₂ eq. CTUe CFC-11 eq. MJ eq.LCIA - Egg ProductionFeed Manure Pullets Electricity Transport Diesel Water0%10%20%30%40%50%60%70%80%90%100%SO₂ eq. N eq. CO₂ eq. CTUe CFC-11 eq. MJ eq.LCIA - Egg GradingEgg production Packaging Electricity WaterFigure 5. Acidifying emissions (kg SO2 eq.), eutrophying emissions (kg N eq.), greenhouse gasemissions (kg CO2 eq.), ecotoxicity (CTUe), ozone depletion (CFC-11 eq.), and fossil CED (MJ eq.)associated with the production of one ton of eggs.3.3.4. LCIA Results—Classification SectorWhen evaluating the results of the classification sector, it is possible to identify thatthe greatest impacts in all analyzed categories stem from egg production, consequentlyincluding the impacts of feed production, pullets, and manure management. Packagingdemonstrated a higher contribution to impacts in categories related to GHG emissions(4.1%), ozone depletion (8.9%), and fossil CED (25.3%) from fossil-based plastic packaging(combs, acrylic lids, and plastic film) and cardboard boxes. Other inputs, such as electricityand water, contribute less than 1% to the impact generated in the production of one ton ofclassified and packaged eggs. Figure 6 illustrates the percentage of impacts generated bythe production of one ton of classified eggs.Animals 2024, 14, x FOR PEER REVIEW 17 of 27 Figure 5. Acidifying emissions (kg SO2 eq.), eutrophying emissions (kg N eq.), greenhouse gas emissions (kg CO2 eq.), ecotoxicity (CTUe), ozone depletion (CFC-11 eq.), and fossil CED (MJ eq.) associated with the production of one ton of eggs. 3.3.4. LCIA Results—Classification Sector When evaluating the results of the classification sector, it is possible to identify that the greatest impacts in all analyzed categories stem fro egg production, consequently including the impacts of feed production, pullets, and manure management. Packaging demonstrated a higher contribution to impacts in categories related to GHG emissions (4.1%), ozone depletion (8.9%), and fossil CED (25.3%) from fossil-based plastic packaging (combs, acrylic lids, and plastic film) and cardboard boxes. Other inputs, such as electricity and water, contribute less than 1% to the impact generated in the production of one ton of classified and packaged eggs. Figure 6 illustrates the percentage of impacts generated by the production of one ton of classified eggs. Figure 6. Acidifying emissions (kg SO2 eq.), eutrophying emissions (kg N eq.), greenhouse gas emissions (kg CO2 eq.), ecotoxicity (CTUe), ozone depletion (CFC-11 eq.), and fossil CED (MJ eq.) associated with the classification of one ton of eggs. 0%102030405060708090100SO₂ eq. N eq. CO₂ eq. CTUe CFC-11 eq. MJ eq.LCIA - Egg ProductionFeed Manure Pullets Electricity Transport Diesel Water0%10%20%30%40%50%60%70%80%90%100%SO₂ eq. N eq. CO₂ eq. CTUe CFC-11 eq. MJ eq.LCIA - Egg GradingEgg production Packaging Electricity WaterFigure 6. Acidifying emissio s (kg SO2 eq.), eutrophying emissions (kg N eq.), greenhouse gasemissions (kg CO2 eq.), ecotoxicity (CTUe), ozone depletion (CFC-11 eq.), and fossil CED (MJ eq.)associated with the classification of one ton of eggs.Animals 2024, 14, 861 16 of 253.3.5. LCIA Results—Liquid Egg ProductionIn all analyzed categories, the greatest impacts stem from the egg classification sector,consequently encompassing the impacts of egg production, pullets, and feed. Consideringthe impacts generated by acidifying emissions, egg production accounts for 99.1%. Foreutrophying emissions, egg production contributes 99.2%. In terms of greenhouse gasemissions, egg production corresponds to 92.1% and transportation to 7.1%. In terms ofecotoxicity, egg production constitutes 97.4%, with transportation contributing 2.5%. Ozonedepletion is primarily driven by egg production at 82.7%, with transportation at 11.8%, gasat 3.4%, and electricity at 1.9%. Fossil CED is dominated by egg production at 70.8%, withtransportation at 24.8%, gas at 2.2%, and electricity at 1.7% of the generated impacts. Otherinputs, such as packaging and water, contribute less than 1% to the impacts generated inthe production of one ton of liquid eggs. Figure 7 illustrates the percentage of impactsgenerated by the production of one ton of liquid eggs.ni als , , x FOR PEER REVIEW 18 of 27 3.3.5. LCIA Results—Liquid Egg Production In all analyzed categories, the greatest impacts stem from the egg classification sector, consequently enco passing the impacts of egg production, pullets, and feed. Considering the i pacts generated by acidifying emissions, egg production accounts for 99.1%. For eutrophying emissions, egg production contributes 99.2%. In terms of greenhouse gas e issions, egg production corresponds to 92.1% and transportation to 7.1%. In terms of ecotoxicity, egg production constitutes 97.4%, with transportation contributing 2.5%. Ozone depletion is primarily driven by egg production at 82.7%, with transportation at 11.8%, gas at 3.4%, and electricity at 1.9%. Fossil CED is dominated by egg production at 70.8%, with transportation at 24.8%, gas at 2.2%, and electricity at 1.7% of the generated impacts. Other inputs, such as packaging and water, contribute less than 1% to the impacts generated in the production of one ton of liquid eggs. Figure 7 illustrates the percentage of impacts generated by the production of one ton of liquid eggs. Figure 7. Acidifying emissions (kg SO2 eq.), eutrophying emissions (kg N eq.), greenhouse gas emissions (kg CO2 eq.), ecotoxicity (CTUe), ozone depletion (CFC-11 eq.), and fossil CED (MJ eq.) associated with the production of one ton of liquid eggs. 4. Discussion The production of feed is directly related to the production of pullets, laying hens (eggs), and, consequently, the generation of organic compounds through the produced manure. In the United States, as reported by Pellitier et al. [28], feed production’s primary impacts are attributed to animal co-products in feed composition, particularly those derived from ruminants. The composition of feed for pullets and laying hens in Brazil differs, with corn and soy identified as the major contributors to its environmental impact. In pullet feed production, a higher concentration of soy derivatives (27%), an elevated concentration of meat and bone meal (4%), and the non-adoption of corn-derived co-products (DDG) contribute to high values of greenhouse gas (GHG) emissions, ecotoxicity, and fossil CED. However, corn comprises 65% and 62% of the composition of pullet and laying hen feed, respectively. Through a comparison of these feeds, it becomes apparent that the incorporation of DDG in laying hen feed has already led to a reduction in the generated impacts. As part of an improvement plan, reconsidering the composition of pullet feeds to meet nutritional requirements without compromising bird development could contribute to enhancing the environmental footprints of the entire production system. 0%10%20%30%40%50%60%70%80%90%100%SO₂ eq. N eq. CO₂ eq. CTUe CFC-11 eq. MJ eq.LCIA - Liquid Egg ProductionEggs Transport Electricity Packaging Gas WaterFigure 7. Acidifying emissions (kg SO2 eq.), eutrophying emissions (kg N eq.), greenhouse gasemissions (kg CO2 eq.), ecotoxicity (CTUe), ozone depletion (CFC-11 eq.), and fossil CED (MJ eq.)associated with the production of one ton of liquid eggs.. iscussionhe production of f ed is directly related to the production of pullets, laying hens( s), and, consequently, the generation of organic compounds through the produceda re. In the United States, as reported by Pell tier et al. [28], feed production’s primaryi cts attributed to animal co-products in feed comp sition, particularly those derivedfrom ruminants. The compositi n of feed for pullets and laying hens in Brazil d ffers, withcorn and soy identified as the major contributors o its environmental i pact. In pulletfeed production, a higher concentrati of soy derivatives (27%), an elevated conc ntrationof meat nd b ne meal (4%), and the non-adoption of corn-derived co-products (DDG)contribute to high values of greenhouse gas (GHG) emis ions, ecotoxicity, and fossilCED. However, corn comprises 65% and 62% of the composition of pullet and laying henfeed, respectively. Through a comparison of these feeds, it becom s apparent that theinco poration of DDG in layi g hen feed has already l to a reduction in the generatedimpacts. As part of an improvement plan, econsidering th compos tion of pullet feeds tomeet nutritional requirements witho t compromising bird development could contributet enhancing th environme tal footprints of the entire oduction system.In both pullet and egg production, the most substantial impacts come from feed andmanure management. The regionalized supply of feed ingredients already plays a role inenhancing sustainability performance in raw material acquisition for the farm. As partAnimals 2024, 14, 861 17 of 25of an improvement plan in manure management, promoting the development of newformulations/compositions of feeds for the pullet and laying phases can contribute to thereduction in gas emissions from intensive animal production systems. According to Hsu,Lin, and Chiou [76], high rates of crude protein can improve productive performance butmay result in a significant increase in uric acid in the animals’ blood plasma, leading to ex-cess elimination through excreta. Therefore, incentivizing the creation of feed formulationsthat balance protein content to maintain productivity while minimizing environmentalimpacts could be a beneficial strategy.Optimizing and managing the duration of the laying cycle can be a significant contrib-utor to sustainability in production. In this study, variations in laying cycles were identified,ranging from 105 to 125 weeks, including the molting process. Future studies with a specificfocus on determining the optimal balance between economic resources and environmentaloutcomes can be conducted to assess the efficiency of different laying cycles. This approachhas the potential to offer valuable insights into achieving optimal sustainability in eggproduction systems.The impacts generated from the grading sector are the same for egg production, withthe additional consideration of energy expenses for egg grading and the use of packaging.As part of an improvement plan, measures related to energy efficiency and alternativepackaging solutions should be considered to mitigate and minimize environmental impactsassociated with the grading process. The adoption of more energy-efficient technologies andthe exploration of eco-friendly packaging options can play an important role in promotinga more sustainable and environmentally friendly egg production and grading system.The production of liquid eggs has emerged as a tool to re-utilize cracked or designatedfor disposal eggs, contributing to the reduction in manure. The market for liquid/processedeggs is experiencing growth both domestically and internationally. Despite incurringadditional costs such as energy, transportation, and packaging, liquid egg productiontransforms what would be considered manure into a product that finds its way back tothe consumer’s table. In this assessment, the most significant impacts related to liquidegg production (excluding egg production itself) are associated with the transportationof eggs to the receiving and processing unit. The receipt of cracked eggs (Type B) mayneed transportation from different states due to the logistics of collecting Type B eggsfrom various farms throughout Brazil. As part of an improvement plan, optimizingtransportation logistics and exploring energy-efficient means of transportation could beconsidered to minimize the environmental impacts associated with this aspect of liquidegg production.The production of organic compost serves as an alternative for reuse and environmen-tal control within the composting area. The farm considers organic compost productionas its second-largest output and sees potential in this market, especially considering thefarm’s geographic location. As a result, there is an assessment of the environmental im-pacts generated by the composting area, which subtracts emissions resulting from theuse of organic compost. This highlights that the anaerobic digestion of manure can beenvironmentally beneficial in other sectors of livestock farming. The overall approachaligns with sustainable practices, promoting the recycling and reuse of organic materialswhile minimizing environmental impacts. This commitment to sustainability reflects aholistic perspective that embraces responsible resource management and contributes to thefarm’s overall environmental stewardship.While the farm’s energy use contributes partially to the environmental impacts ofthe egg production life cycle, there is a broad range of technologies on the market toimprove energy efficiency in production. For instance, the adoption of solar panels couldsignificantly enhance energy efficiency compared to the use of diesel generators andwood, which, in this study, introduced uncertainties in the data due to a lack of controlover the quantity of wood used and the periods of use for diesel generators. Collectingdetailed data on energy sources and quantities consumed in each sector would empowerproducers to better understand how energy use affects the sustainability of their production.Animals 2024, 14, 861 18 of 25Implementing more sustainable and efficient energy practices, such as the adoption ofsolar panels or other renewable energy sources, can play an important role in reducing theenvironmental footprint of egg production. This shift toward cleaner and renewable energysources aligns with sustainable practices and contributes to the overall environmentalresponsibility of the farm.4.1. Result of Data Sensitivity AnalysisThe choice of impact assessment method can play an important role in estimating theenvironmental impacts attributed to any product or system. In order to investigate theeffects of this choice, additional analyses were performed using alternative LCIA methods.The calculation of GHG emissions was considered using the IPCC 2021 and CML 2016methods, which resulted in reductions of approximately 2.4% and 3.5% in GHG emissions,respectively, as shown in Table 12.Table 12. GHG emissions associated with the production of 1 ton of eggs using TRACI 2.1, IPCC2021, and CML 2016 methods.TRACI 2.1 IPCC 2021 CML 2016GHG emissions (kg CO2 eq.) 3107.90 3033.25 2999.53Relative % 100 97.60 96.51Thus, the use of alternative LCIA methods may yield differences in the estimates ofother generated impacts. Therefore, it is important to emphasize the significance of select-ing and consistently applying a single impact assessment methodology for comparativepurposes in future assessments.4.2. Results of Data Quality and UncertaintyAt first glance, the quality of input data for most processes is generally considered high,with the exception of the evaluation of impacts associated with chick acquisition and theutilization of wood-burning generators. Nevertheless, these findings hold less significancein the context of the LCA of egg production. The data pertaining to the quantity of water,fuel, and manure generated were approximated based on the total annual informationprovided by the farm itself. To mitigate uncertainties in LCA models for the Brazilianegg industry, forthcoming assessments should prioritize enhancing the modeling of feedinventory, ensuring precise control over energy expenditures (energy use), and fostering thedevelopment of models to monitor and quantify resource consumption in specific sectors,such as water and fuel.One of the primary challenges encountered is estimated to be the access limitationsto data and the identified gaps in certain information during this study. Beyond the datasupplied by the farm, the expansion of the national inventory database is imperative, mark-ing a significant impediment to the advancement of LCA due to the extensive volume ofnecessary data. Nonetheless, ongoing research endeavors are dedicated to the adoption anddissemination of LCA in Brazil, with a specific emphasis on consolidating the methodologyand establishing a comprehensive database to bolster LCA efforts.The second major challenge encountered pertained to the modeling of emissions frommanure management systems. In this analysis, a combination of IPCC Tier 1 and 2 methods,coupled with a standardized loss rate, was employed to calculate phosphorus (P) losses.While the utilization of models is generally necessary for estimating emissions in an LCAdue to measurement complexities, it is important to acknowledge that the use of modelscan introduce uncertainties into the proposed framework. All modeling processes fornitrogen (N), phosphorus (P), and methane (CH4) emissions were meticulously devel-oped and computed with the aim of directing future assessments toward the control ofthese emissions.Animals 2024, 14, 861 19 of 254.3. Result of Comparisons with Other StudiesTable 13 displays values related to the LCIA of battery cage egg production systems invarious countries. In this study, the values correspond to 0.07 kg SO2 eq.; 3.1 kg CO2 eq.;75.98 CTUe.; 2.77 × 10−5 kg CFC-11 eq.; and 10.07 MJ eq. per kilogram of eggs produced.Table 13. LCIA considers acidifying emissions, eutrophying emissions, GHG emissions, ecotoxicity,ozone layer depletion, and fossil CED per kilogram of eggs produced in international evaluations.Reference Country Acidification(kg SO2 eq.)Eutrophication(kg PO4 eq.)GHG(kg CO2 eq.)Ecotoxicity(CTUe)OzoneDepletion (kgCFC-11 eq.)CED Fossil(MJ eq.)In this study Brazil 0.07 _ 3.1 75.98 2.77 × 10−5 10.07Guillaume et al. [22] CzechRepublic _ _ 2.46 62.87 8.46 × 10−8 13.33Turner et al. [23] Canada 0.08 0.03 2.36 _ 2.30 × 10−6 _Estrada-Gonzálezet al. [27] Mexico _ _ 5.58 _ 2.70 × 10−7 _Abín et al. [29] Spain _ _ 3.50 _ _ _Pelletier [24,25] Canada 0.08 0.02 2.44 _ _ 11.25Pelletier et al. [28] USA 0.07 0.02 2.10 _ _ 12.30Leinonen et al. [30,31] UnitedKingdom 0.06 0.02 2.92 _ _ 16.80Wiedemann eMcGahan [32] Australia _ _ 1.4 _ _ _Mollenhorst et al. [33] Netherlands 0.03 0.02 3.9 _ _ _Cederberg et al. [34] Sweden _ _ 1.4 _ _ _Vergé et al. [26] Canada _ _ 2.5 _ _ _Regarding the emission results, it is evident that acidifying and eutrophying emissionsexhibit minimal variations in their outcomes. Concerning ecotoxicity and ozone depletion,the current study observed an increase of 13.11 CTUe and 2.76 × 10−5, respectively, incomparison to the assessment conducted by Guillaume et al. [22]. Conversely, in the contextof fossil CED, this study demonstrated a reduction of 6.73 in comparison to the evaluationscarried out by Leinonen et al. [30,31].The values associated with CO2 equivalent emissions in LCIA for egg productionremain consistent across all assessments, ranging from 1.4 to 5.58 kg of CO2 eq. per kg ofegg produced over the years 2006 to 2022. The battery cage production system in countriessuch as the Czech Republic, Canada, the USA, the UK, Australia, and Sweden exhibitslower carbon footprints than Brazilian egg production. In contrast, Mexico, Spain, andthe Netherlands show carbon footprints larger than those of Brazilian egg production. Itis noteworthy that in this study, eutrophying emissions represent a value of 0.03 kg N eq.Table 14 presents values related to the LCIA of Brazilian productions, encompassing beefcattle, dairy cattle, broiler chickens, pigs, and feed for broiler chickens across variousproduction systems.LCA studies for beef cattle in various production systems reveal the highest CO2equivalent emissions per kilogram produced, with values ranging from 9.16 to 22.52 kgCO2 eq./kg live weight and 18.32 to 58.3 kg CO2 eq./kg carcass weight. In some LCAstudies on dairy cattle, the production system may not be specified, but the focus is onthe production form, such as confined, semi-confined, and pasture, with values rangingfrom 0.54 to 1.83 kg CO2 eq./kg milk. Regarding pig LCA studies, many are dedicatedto evaluating different manure management systems. In the assessment proposed byCherubini [72], the values range from 3.11 to 3.55 kg CO2 eq./kg live weight within theconsidered manure management system. In assessments related to feed production, theinfluence of sourcing main inputs (corn and soy) close to the feed factory is evident, varyingbetween 0.51 and 0.75 kg CO2 eq./kg feed.Animals 2024, 14, 861 20 of 25Table 14. LCIA considers CO2 eq. emissions in Brazilian productions of beef cattle, dairy cattle,broiler chickens, pigs, and feed for broiler chickens in their different production systems per kilogramproduced.Reference State/Region Product Production System GHG Emissions (kg CO2eq./kg Produced)Dick et al. [61] Rio Grande do Sul Beef cattle Extensive and Intensive22.52 (Live weight) and45.05 (Carcass weight) inextensive; 9.16 (Liveweight) and 18.32 (Carcassweight) in intensive.Cardoso et al. [62] Central-west(Cerrado)Beef cattle (in 5different scenarios)Extensive eSemi-intensive58.3(C1); 40.9(C2); 29.6(C3);32.4(C4); 29.4(C5) (All inCarcass weight).Willers et al. [63] Bahia Beef cattle Semi-intensive 9.43 (Live weight).Dick et al. [64] Amazonas, Cerrado,Pampa, and Pantanal Beef cattle ExtensiveAmazonas 13.92, Cerrado12.10, Pampa 14.62,Pantanal 21.18 (All in liveweight).Leis et al. [65] Paraná and SantaCatarinaDairy cattle (ECM:energy-correctedmilk)Confined,semi-confined, andpasture0.54 confined; 0.78semi-confined; 0.74pasture.Carvalho et al. [66] Middle Southwestregion of BahiaDairy cattle (FPCM:fat and proteincorrected milk)Semi-intensive 1.41Barros et al. [67] Paraná and MinasGeraisDairy cattle (FPCM:fat and proteincorrected milk)Confined,semi-confined1.14 confined in PR; 1.64semi-confined in PR; 1.83semi-confined in MG.Maciel et al. [68] Minas GeraisDairy cattle (with andwithout manuretreatment byanaerobic digestion)Semi-intensive 0.88 (with treatment); 1.16(without treatment)Silva et al. [69] Central west andsouth of Brazil Broilers Intensive2.06 (Centro oeste) 1.45(Sul)Lima et al. [70] Mato Grossodo Sul Broilers Intensive 2.70Alves et al. [71] Rondônia Broilers Intensive 3.37Cherubini et al. [72] _Swine (in 4 manuremanagementsystems)Intensive3.50 in tanks, 3.39 inbiodigestor (a), 3.11 inbiodigestor (b), 3.55 incomposting.Alvarenga et al. [73] Santa Catarina Broiler feed _0.75 (CW–CW) *; 0.58(CW–SO) *; 0.68 (SO–SW) *;0.51 (SO–SO) *.* CW and SO represent the central-western and southern regions of Brazil, with the acquisition of maize andsoybean inputs, respectively.However, when evaluating the environmental impacts of Brazilian agro-industrialproductions, egg production represents impacts relatively close to the average impacts ofbroiler chicken and pig production.5. ConclusionsIn conducting an LCA following ISO 14044, including the cradle-to-gate farm scopeand cut-off and exclusion criteria for the battery cage egg production systems and re-lated products in Brazil, environmental impacts were quantified through emissions at-Animals 2024, 14, 861 21 of 25tributable to the intensive egg production system. Emissions related to egg productionwere measured at 65.06 kg SO2 eq., 27.74 kg N eq., 3086.71 kg CO2 eq., 75,152.66 CTUe,2.75 × 10−5 CFC-11 eq., and 10,044.68 kg MJ eq. per ton of eggs produced. When consid-ering egg classification, emissions slightly increased to 65.78 kg SO2 eq., 28.26 kg N eq.,3232.93 kg CO2 eq., 76,676.23 CTUe, 3.04 × 10−5 CFC-11 eq., and 13,541.11 kg MJ eq. perton of eggs produced and classified. Finally, the production of processed liquid eggsin another unit of the farm resulted in emissions of 85.30 kg SO2 eq., 36.33 kg N eq.,4355.12 kg CO2 eq., 100,286.33 CTUe, 4.33 × 10−5 CFC-11 eq., and 18,436.53 kg MJ eq. perton of liquid eggs produced.When comparing battery cage egg production systems in various countries, it has beenobserved that countries like the Czech Republic, Canada, the USA, the United Kingdom,Australia, and Sweden demonstrate lower carbon footprints compared to Brazilian pro-duction. Conversely, Mexico, Spain, and the Netherlands exhibit higher carbon footprints.However, within the broader context of evaluating the environmental impacts of Brazilianagro-industrial productions, egg production consistently stays, on average, between theimpacts associated with broiler chicken and pork production.After a comprehensive evaluation of all impacts, it becomes evident that interventionsfocused on feed formulation, manure management, and the welfare of laying hens playpivotal roles in promoting sustainability within the battery cage egg production system.Managing sustainability poses both challenges and opportunities for the Brazilian eggindustry. However, nutrition-related interventions, management practices (consideringimproved animal welfare, public health, and biodiversity loss), and the adoption of newtechnologies in the production system hold significant promise for achieving genuinesustainability in production.As the first LCA of the Brazilian egg industry, considering a single Brazilian farm withhigh production potential, the presented results can serve as comparative benchmarks forfuture studies and analyses of data in different egg production systems in Brazil. Thesefindings provide a foundation for ongoing efforts to enhance sustainability practices withinthe industry and offer valuable insights for stakeholders seeking to implement effectiveinterventions for a more sustainable egg production system in the country.Supplementary Materials: The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/ani14060861/s1, Table S1: Calculation of nitrogen emissions,methane, and phosphorus losses, considering the functional unit of 1000 hens produced in cages.Table S2. Calculation of nitrogen emissions, methane, and phosphorus losses, considering thefunctional unit of one ton of eggs produced. Table S3: Compositions of the feeds for the Pulletshouses. Table S4: Compositions of the feeds for the Laying houses. Table S5: Data quality criteriaand rating system: ecoinvent pedigree matrix. Table S6: Data quality assessment: ecoinvent pedigreematrix.Author Contributions: Conceptualization, F.d.F.M., R.S.G., I.d.F.F.T., N.P., M.A.I.-B., N.d.S.R. andF.C.d.S.; writing—original draft preparation, F.d.F.M.; supervision, R.S.G., I.d.F.F.T., N.P., M.A.I.-B.,N.d.S.R. and F.C.d.S.; validation, visualization, and writing—review and editing, R.R.A., G.M.d.M.S.and V.B. All authors have read and agreed to the published version of the manuscript.Funding: This research was funded by the Coordination of Superior Level Staff Improvement, Brazil(CAPES)—Finance Code 001; the National Council for Scientific and Technological Development,Brazil (CNPq)—Process 422912/2018-2; and the Minas Gerais Research Support Foundation, Brazil(FAPEMIG)—Finance Code 001.Institutional Review Board Statement: As our research project does not involve direct work withanimals and other farm professionals, the project advisors and the postgraduate program approvedthat it did not need to be forwarded to the ethics committee. All data used in this research were sentthrough the farm’s administrative manager.Animals 2024, 14, 861 22 of 25Informed Consent Statement: Informed consent was obtained from the farm director involved in thestudy.Data Availability Statement: The data presented in this study are available upon request from thecorresponding author.Acknowledgments: The authors would like to thank the Federal University of Viçosa (UFV), theFederal Institute of Education, Science, and Technology of the South of Minas Gerais—CampusInconfidentes (IFSULDEMINAS), Iowa State University (ISU), and the University of British Columbia(UBC), whose support is appreciated.Conflicts of Interest: Author Guilherme Moreira de Melo Silva is employed by the company Man-tiqueira Brasil. The remaining authors declare that the research was conducted in the absence of anycommercial or financial relationships that could be construed as a potential conflict of interest.References1. ABPA. 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agricultural sector
egg production
intensive system
sustainability
LCA
LCI
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Environmental Impacts of the Brazilian Egg Industry: Life Cycle Assessment of the Battery Cage Production System
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