Abstract
The phenotype of organisms is not only influenced by genetic factors, but also by environmental factors that play a critical role in shaping their morphology, physiology, behavior and reproductive capacity. In avian species, maternal influences have aroused much attention after the discovery that avian eggs contain a variety of maternal derived steroid hormones. Precocial birds offer a useful animal model so as to solve the mother-offspring interference problem. By removing the maternal effect, scientists can evaluate the effect of glucocorticoid exposure during the embryonic development and its effects on later of phenotypic traits. However, the study of bird's aggressive behaviors using in ovo injection of hormone has not been reported. We used in ovo injection of corticosterone to study aggressive and fearfulness behaviors in chicken in their life later.•Fertilized chicken egg consider as pregnant mother•In ovo injection of corticosterone by pass mother-offspring interference problem•The method allow scientist to evaluate the influences of stress hormone on embryonic development and its later life consequences.