Animal welfare

Genetic relationship between feather cover and survival in crossbred laying hens

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Abstract

Pecking and cannibalism are major welfare and productivity problems in laying hens, leading to feather loss and excess mortality. Our objective was to estimate genetic parameters for survival and feathering and to quantify their genetic association. Data comprised 3,132 A×B hens from 160 sires (A), with pedigree records up to five generations. Birds were kept in three houses (One generation per house) in 647 cages (4-6 per cage). Individual survival in weeks was recorded, and hens that stayed alive until end of lay were assigned 100 weeks. Feathering was scored per cage on a continuous linear scale from 1 to 9 (higher is better), with each score representing the average of evaluations from three independent observers. Feathering was recorded at 40, 75 and 90 weeks. Cages were structured by sire family (≈75% full-sibs and ≈25% paternal half-sibs), with survival recorded individually and feather cover at cage level. In this group-housing system, direct and social genetic effects are confounded when using only pedigree data, so the key selection criterion becomes the total genetic effect, expressed as the total breeding value (TBV). Accordingly, a sire model can be used to estimate sire-level transmitting ability for group outcomes, which serves as a practical proxy for TBV. Therefore, a bivariate sire model was fitted in gibbsf90+ (BLUPF90). For survival, fixed effects included house/generation (3 levels), cage density at placement. Random effects were cage (diagonal), sire additive genetic effect (paternal pedigree).For feathering, fixed effects included house, recording time (40, 75 and 90 weeks), cage density at placement, and current cage density at each scoring time, with random cage and sire additive genetic effects. Posterior means and 95% highest posterior density intervals are reported. Overall mortality at the end of lay was 8.3%, and mean cage-level feathering score was 5.4±1.9. Total heritability (T2= σ2AT / σ2P, where σ2AT = 4σ2s) estimates were low to moderate (0.16 ± 0.06) for survival and moderate (0.34 ± 0.10) for feathering. The additive genetic covariance was positive, resulting in a strong favorable genetic correlation, rg= 0.79 [0.46 - 1.00], indicating that better feather cover is genetically associated with higher survival. Cage effects explained an important proportion of phenotypic variance, with 0.19 ± 0.02 for survival and 0.27 ± 0.03 for feathering. The cage correlation was essentially zero, rc= -0.03 [−0.19, 0.14], suggesting that cage-to-cage deviations affecting survival were not aligned with those affecting feather score. The strong favorable genetic relationship indicates that improving feather cover through selection is expected to increase survival. The near-zero cage correlation suggests this linkage is primarily genetic rather than driven by shared cage conditions. Consequently, feather score represents an important indicator trait to drive correlated gains in survival within commercial group housing systems.

Keywords: 2026

How to Cite:

BIADA, I., Casto Rebollo, C., Cavero Pintado, D. & Ibáà±ez Escriche, N., (2026) “Genetic relationship between feather cover and survival in crossbred laying hens”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2285390. doi: https://doi.org/10.31274/wcgalp.23677

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