Sequential and choice feeding in laying hens: adapting nutrient supply to requirements during the egg formation cycle

Conventional feeding systems for laying hens rely on a complete feed available ad libitum in mash, pelleted or crumble form. When complete feeds are used, intake is mainly controlled by the hens' energy requirement and feed presentation, but the birds cannot adjust their consumption to other nutritional needs and thus over-consume to cover the calcium needed for egg shell formation. Sequential, loose-mix and choice feeding offer birds the opportunity to select different diets in the short term. These feeding strategies have been proposed as alternative feeding systems whose main objectives are to match nutrient supply to individual requirements during the daily changes induced by the temporal sequence of the egg formation. This review discusses some findings related to the use of whole cereals and of alternating low and high energy or protein diets, conditions which may improve feed utilisation efficiency. In addition, the adjustment of calcium and phosphorus levels during the day can have benefits in terms of egg production and quality. This review explores the physiological basis for sequential, loose-mix and choice feeding and evaluates the impact of these systems on egg production and quality.