Split feeding for laying hens: a step beyond precision nutrition.

The primary objective of modern laying hen production is to extend the production cycle to achieve an average of 500 eggs in 100 weeks, which requires research to improve eggshell quality. The eggshell plays a crucial role in mechanical protection and provides a suitable environment for embryonic development. Composed mainly of calcium carbonate and other minerals, calcium (Ca) is essential in the diet for eggshell formation and is incorporated into the diet of laying hens. However, hens have a cyclic reproductive physiology, which leads to varying nutrient requirements throughout the day. In the morning, higher levels of dietary protein and energy are needed to support yolk and albumen formation, while in the afternoon and evening, increased calcium intake is crucial for eggshell and membrane development. Traditional feeding systems, which provide a single diet throughout the day, may result in nutrient imbalances, leading to excess calcium intake in the morning and an oversupply of protein and energy in the afternoon. To address this issue, the split feeding strategy has been proposed. This approach involves offering a high-protein, high-energy, low-calcium diet in the morning, followed by a low-protein, low-energy, high-calcium diet in the afternoon or evening. By aligning nutrient supply with the hen's metabolic needs, split feeding optimizes nutrient utilization, improves feed efficiency, and enhances eggshell quality while reducing unnecessary nutrient excretion. Given the growing interest in optimizing layer nutrition and improving production efficiency, this study presents a comprehensive review of existing data on split feeding strategies, highlighting their impact on nutrient utilization, eggshell quality, and overall laying performance.