Unravelling early feeding in broiler chicks: Early-life physiological responses and welfare trade-offs from hatch to later life

Korte beschrijving

Early feeding is receiving increasing attention in modern broiler production as a potential strategy to improve welfare, development, and performance. In conventional hatcheries, chicks may remain without access to feed and water for 48–72 h after hatch due to the biological hatch window, hatchery procedures, and transport. Although the residual yolk provides temporary support during this period, concerns remain regarding hunger, thirst, and physiological stress. On the other hand, early feeding may stimulate growth and muscle development, with potential adverse consequences for locomotion and meat quality. This thesis therefore investigated the short- and long-term effects of early feeding in fast-growing Ross 308 and slower-growing Hubbard Redbro broilers, under both conventional hatchery and on-farm hatching conditions. The first study investigated the physiological effects of feed and water availability during the first 48 h post-hatch. Chicks received access to feed and water, feed only, water only, or neither. Access to both feed and water increased body weight from 24 h onwards, whereas water alone limited body weight loss. Chicks without access to water showed higher plasma osmolality, and fully deprived chicks had the highest arginine vasotocin concentrations, while corticosterone was lowest when both feed and water were available. Ghrelin mRNA expression decreased in chicks with access to feed and water, suggesting that feed intake probably started between 14 and 24 h post-hatch. These results show that chicks begin eating and drinking relatively early and that access to both feed and water supports their physiological condition during the first days of life.