Feed pecking in young chickens: new techniques of evaluation.

Three techniques were compared: automated recording (A) of 2 h of feeding activities conveyed to a computer by constantly connected electronic balances, videotaping (V) of a closeup of the head of a chick during a feed-pecking session analyzed by focal sampling at reduced speed (16 times slower), strength of pecking (S) at feed particles recorded from a feeder-weight signal conveyed to a computer by a customized electronic balance at rapid speed (24 times/s). These techniques were applied to 16-18-day-old chicks fed either a complete feed or a split diet (whole grain wheat + a complementary feed). The two feeds had similar pellet forms. The complementary feed particles were eaten at a slower rate than the complete feed particles (A and V techniques). Wheat grains were pecked with a weaker measured strength than the pellets (technique S). Two pecks of three did not result in prehension of a feed particle and were categorized as "exploratory" pecks. For 75% of the time during a continuous pecking session the head of the chick was in a static position, suggesting a long period of observation of the feed between 2 consecutive pecks. Videotaping with slow-motion focal sampling (V) offers potential development for the study of food intake behavior of chickens.