Delayed post-hatch feeding effects in broilers delayed post-hatch feeding alters stress physiology and skeletal development in on-farm hatched slower-growing broiler chickens

Early post-hatch nutrition is an important factor influencing broiler health and welfare. This study investigated the effects of delayed access to feed on production and health-related outcomes in slower-growing Hubbard Redbro broilers throughout the production cycle. Three treatments were tested: T0 (immediate access to feed), T24 (24 h delay), and T48 (48 h delay). Physiological, morphological, and welfare-related outcomes were assessed through plasma corticosterone (CORTp), bone measurements, skeletal fluctuating asymmetry (FA), gait score, litter moisture, and femur head necrosis (FHN). Delayed post-hatch feeding altered CORTp dynamics in a time-dependent manner. On day 2, T48 birds tended to have lower CORTp compared to T0 (p = 0.068) and T24 (p = 0.089), while this pattern reversed on day 3, with T0 birds showing elevated corticosterone compared to both T24 (p = 0.013) and T48 (p = 0.005). Humerus length was reduced in the T48 group (p = 0.002), and the composite FA index followed a non-linear pattern, with the lowest asymmetry in T24 and the highest in T48. No differences were found in gait score, litter moisture, or FHN. Overall, delayed post-hatch feeding had measurable short-term physiological and long-term morphological effects, but did not compromise welfare-related indicators by the end of the production cycle.