Cortisol and Corticosterone in Poultry

This record presents a critical narrative review on cortisol and corticosterone in poultry, with emphasis on recent research and practical interpretation for welfare assessment. Corticosterone remains the principal glucocorticoid recognized in poultry physiology, but cortisol has been detected in avian blood, tissues, and egg albumen, raising new questions about its physiological role and whether it should be measured alongside corticosterone. The review examines selected recent studies, including a 2025 laying-hen study on age-related hypothalamic–pituitary–adrenal (HPA) axis responses to ACTH, and a 2026 broiler study on the effects of scalding on feather corticosterone concentrations. Together, these studies illustrate that detecting a hormone, obtaining a concentration, and drawing a conclusion about flock welfare are distinct steps. Hormone results should therefore be interpreted alongside species, age, sample type, collection and processing conditions, analytical validation, and complementary health, behavioral, and production indicators. The evidence supports further investigation of cortisol, but does not establish a routine requirement to measure cortisol and corticosterone together in every commercial flock. This review is intended for researchers, veterinarians, poultry nutritionists, and industry professionals interested in evidence-based welfare assessment. It is a focused narrative review, not a systematic review or an exhaustive account of all published studies.