Commercial layer hybrids kept under organic conditions: a comparison of range use, welfare and egg production in two layer strains

The influence of genetic strain on production and egg quality amongst four strains of laying hens housed in a cage-free environment

As the United States egg industry transitions towards cage-free production, genetic strains must be evaluated in their performance in these alternative environments. Transitioning strains that were selected for caged production may elicit challenges in their adaptation to alternative systems, so it cannot be assumed that egg production and quality parameters are comparable in various environments. White strains are historically associated with caged production while brown strains typically occupy cage-free systems. Therefore, the aim of this study was to evaluate the influence of genetic strain on egg production and quality in a cage-free environment. Hy-Line W-36 White, H&N White, Hy-Line Brown, and Bovan Brown laying hen strains were evaluated through numerous egg production and quality parameters throughout the entirety of a lay cycle. H&N White hens in this study were the lowest producing strain demonstrated by producing the least amount of eggs per hen, having the lowest hen-day egg production (p < 0.0001), producing the fewest USDA grade A eggs (p = 0.0023), and the most check eggs (p = 0.0006). However, the Bovan Browns were the least efficient strain as this strain consumed the most feed and had the lowest feed conversion ratio (p < 0.0001). Overall, both white strains demonstrated poorer egg quality compared to brown strains. Hy-Line W-36 White hens had the lowest albumen height, Haugh unit score, yolk color, and yolk weight (p < 0.0001). H&N Whites had the lowest vitelline membrane strength, shell weight, and shell thickness (p < 0.0001). In conclusion, the Hy-Line Brown hens may be better suited for cage-free production based on overall greater egg production and quality metrics compared to the three other strains used in this study. Therefore, this research demonstrates that genetic strain did influence cage-free laying hen performance.

Proteomics and bioinformatics analyses based on two-dimensional electrophoresis and LC-MS/MS for the primary characterization of protein changes in chicken breast meat from divergent farming systems: Organic versus antibiotic-free

Proteomics is a key analytical method in meat research thanks to its potential in investigating the proteins at interplay in post-mortem muscles. This study aimed to characterize for the first time the differences in early post-mortem muscle proteomes of chickens raised under two farming systems: organic versus antibiotic-free. Forty post-mortem Pectoralis major muscle samples from two chicken strains (Ross 308 versus Ranger Classic) reared under organic versus antibiotic-free farming systems were characterized and compared using two-dimensional electrophoresis and LC-MS/MS mass spectrometry. Within antibiotic-free and organic farming systems, 14 and 16 proteins were differentially abundant between Ross 308 and Ranger Classic, respectively. Within Ross 308 and Ranger Classic chicken strains, 12 and 18 proteins were differentially abundant between organic and antibiotic-free, respectively. Bioinformatics was applied to investigate the molecular pathways at interplay, which highlighted the key role of muscle structure and energy metabolism. Antibiotic-free and organic farming systems were found to significantly impact the muscle proteome of chicken breast meat. This paper further proposes a primary list of putative protein biomarkers that can be used for chicken meat or farming system authenticity.

Early and late cognitive and behavioral aspects associated with range use in free-range laying hens (Gallus gallus domesticus)

Individual differences in free-range chicken systems are important factors influencing how birds use the range (or not), even if individuals are reared in the same environmental conditions. Here, we investigated how various aspects of the birds' behavioral and cognitive tendencies, including their optimism/pessimism, cognitive flexibility, sociability, and exploration levels, are associated with range use and how they may change over time (before and after range access). To achieve this, 100 White Leghorn laying hen chicks underwent three distinct behavioral/cognitive tests-the cognitive bias test, the detour test, and the multivariate test-prior to gaining access to the range, between 9 and 39 days of age. After range access was allowed (from day 71), birds' range use was evaluated over 7 nonconsecutive days (from 74-91 days of age). Subsequently, a subset of birds, classified as high rangers (n = 15) and low rangers (n = 15) based on their range use, underwent retesting on the same three previous tests between 94 and 108 days of age. Our results unveiled a negative correlation trend between birds' evaluation of the ambiguous cue and their subsequent range use (rho = -0.19, p = 0.07). Furthermore, low rangers were faster to learn the detour task (χ2 = 7.34, df = 1, p = 0.006), coupled with increased sociability during the multivariate test (rho = -0.23, p = 0.02), contrasting with their high-ranging counterparts, who displayed more exploratory behaviors (F[1,27] = 3.64, p = 0.06). These behavioral patterns fluctuated over time (before and after range access); however, conclusively attributing these changes to birds' aging and development or the access to the range remains challenging. Overall, our results corroborate that behavioral and cognitive individual differences may be linked to range use and offer novel perspectives on the early behavioral and cognitive traits that may be linked to range use. These findings may serve as a foundation for adapting environments to meet individual needs and improve animal welfare in the future.