Elsevier

Hormones and Behavior

Volume 128, February 2021, 104892
Hormones and Behavior

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

https://doi.org/10.1016/j.yhbeh.2020.104892Get rights and content
Under a Creative Commons license
open access

Highlights

  • In birds contact incubation establishes a sharp temperature gradient within the egg.

  • Conventional incubators, often used in research and industry, warm the egg evenly.

  • We test effects of incubation condition on post-hatch phenotype in Red jungle fowls.

  • Incubation condition affects chicks' growth, stress response and behavior.

  • Our results highlight the embryo's sensitivity to the pre-hatch thermal environment.

Abstract

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

Keywords

Prenatal
Cognition
Fearfulness
Parental care
Development
HPA-axis
Growth

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