Disease & heat resistance

Resilience to heat stress in a commercial line and four autochthonous Spanish breeds of laying hens

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Abstract

Global warming adversely affects egg production. Autochthonous breeds of laying hens are particularly valuable in a climate change context because of adaptation to the local environment. Differences in daily egg production between one commercial line (Hy-Line Brown - HL) and four Spanish breeds of laying hens (Castellana Negra - CN, Andaluza Franciscana - AF, Prat Leonada - PL, Andaluza Azul - AA) was evaluated in five periods (P1-P5) of 50 days each between February and September 2025 (between 11 and 18 months of age) in 60 hens per breed housed in four pens per breed. Average 24h temperature in these periods was 8, 11, 22, 28, and 22˚C, respectively. Animals were kept indoors in a building that was not climate controlled, therefore, animals were subjected to natural climate fluctuations. The autochthonous breeds are maintained at this facility since 1975. HL are bred in climate controlled housing but sibs of selection candidates are exposed to commercial conditions in field tests across multiple locations with varying challenges including heat stress and their information is used for selection. It was hypothesized that hens from local poultry breeds will show a better capacity to maintain production under heat stress than those from high producing commercial lines. Average daily egg production was similar for all breeds in P1 (0.58-0.63 ± 0.299 eggs/day). In the Spanish breeds, average daily egg production was similar between P1 and P2; thereafter production declined between P2 and P5 (to 0.33-0.46 ± 0.299 eggs/day; the lowest value corresponds to AA and was significantly lower than the breeds with the highest values, AF and CN [P< 0.01]). On the contrary, in HL, egg production increased between P1 and P2, and thereafter was similar between P2 and P5 (0.82-0.88 ± 0.299 eggs/day). During P3 and P4, corresponding to daily temperatures between 15 and 32 ˚C, egg production significantly reduced with 0.007 to 0.01 egg/˚C in all Spanish poultry breeds (P< 0.05); the most resilient local breeds were P and AF. No significant relationship was found between temperature and egg production in HL. Commercial high-producing animals are generally thought to be more sensitive to suboptimal environmental conditions. However, our results show that hens from a commercial line produced more eggs with a higher persistency in egg production under heat stress than hens of four local Spanish breeds. Crossbreeding of commercial with local poultry breeds may combine the benefits of high production with adaptation to the local environment. Sustainability of production systems in the context of climate change requires novel breed choice and genetic selection objectives for improved heat tolerance. Of the Spanish breeds, Andaluza Franciscana is a breed of particular interest because it combines high production with high resilience to heat stress.

Keywords: 2026

How to Cite:

Rauw, W., Torres, O., Santiago-Moreno, J., Wolc, A., Peiró-Pastor, R., Toledano-Diaz, A. & Gomez-Raya, L., (2026) “Resilience to heat stress in a commercial line and four autochthonous Spanish breeds of laying hens”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2284127. doi: https://doi.org/10.31274/wcgalp.23549

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