Genotype, feeding regimen, and diet interactions in meat chickens. 2. Feeding behavior

Feeding behaviors were compared for males from two lines of meat chickens differing in growth potential fed lower and higher density diets ad libitum either daily or on alternate days. Males from the faster growing line ate and drank more often but stood and rested less often than those from the slower growing line. Rate of feed intake per unit BW was, however, similar for both lines. Greater crop and lower intestinal contents of the faster growing line suggested a higher feed intake and storage ability. Even though males fed the lower energy diet initially consumed similar amounts of ME on days of food restoration, by 24 h they lagged behind those fed the higher energy diet, suggesting capacity of the gastrointestinal tract (GIT) to be a limiting factor in energy consumption. At older ages, chicks fed the different diets had similar GIT contents, suggesting that excessive eating and less resting observed for males fed the lower density diet contributed to their poorer energy utilization. On the day of feed restoration, males fed on alternate days ate and stood more often and had poorer GIT clearance than those with feed continuously made accessible to them.