Abstract
Feeding timing and feeding frequency (FTF) are important management aspects affecting physiological regulation, nutrient utilization, and productivity in poultry. While ad libitum feeding continues to be common in production, there is increasing evidence that the timing of feeding and timing matching with circadian rhythm, i.e., feeding into several meals, can enhance growth, reproduction efficiency, and adaptation to environmental challenges. This review aims to consolidate the current understanding of how FTF affects gut development, hormone secretion, metabolic balance, and stress response. Biologically ideal feeding at different times of day has been shown to improve the functioning of the gastrointestinal system, enhance the action of anabolic hormones, increase feed intake in cooler weather, and attenuate the heat-induced depression in growth. On the other hand, increasing feeding frequency promotes ongoing nutrient uptake, stabilizes blood metabolism, increases muscle protein accumulation, and decreases aggressive behavior related to feed competition (Wang et al., 2024b). Taken together, these mechanisms enhance the daily average increase, feed conversion ratio (FCR), and flock uniformity. In addition to growth, FTF has effects beyond growth on reproduction itself, via greater energy balance, metabolic stability, and better ovarian activity synchronization. Suitable FTF techniques are required to ensure good intestinal integrity, antioxidant performance, and overall physiological stability in the intestines under heat stress. Nonetheless, responses to FTF are contextually contingent and depend on genetics, age, production-related features, environment, and production purpose, while context-specific management is required for optimal use. This review provides a physiological basis for understanding FTF, serving as a foundation for developing precision feeding strategies that can be used to formulate fine mechanical precision feeding programs to achieve greater efficiency and welfare, that is, sustainably in today’s poultry production.

Key words: Circadian rhythm; Feeding frequency; Feeding time; Heat stress; Poultry production.