Effect of contact incubation on stress, behavior and body composition in the precocial Red jungle fowl

Birds use contact incubation to warm their eggs above ambient temperature required for embryonic development. In contrast, birds in the industry as well many breeding programs and scientific studies are incubated conventional incubators that via circulating air. This means have different thermal properties than a incubator. light of previous showing small differences can affect chicks post-hatching phenotype, we investigated consequences incubating Red jungle fowl at same (37 °C) either or air incubation. We found had more robust body composition, were explorative higher preference early life, sex dependent difference plasma Corticosterone levels pre-hatch (measured down-feathers) post-hatch plasma) compared While demonstrated development phenotype is sensitive variations temperature, our study demonstrates first time way heat distributed egg has similar magnitude effect on highlights sensitivity period shaping phenotype. • establishes sharp gradient within egg. Conventional incubators, often used research industry, evenly. test effects condition fowls. Incubation affects chicks' growth, stress response behavior. Our results highlight embryo's environment.