Energy requirement of feed-restricted broiler breeder pullets

The energy requirements for growth and maintenance of broiler pullets were studied during a 17-wk growing period. Four flocks of commercial broiler replacement pullets, housed in conventional poultry houses, received a restricted amount of feed on 4 or 5 days a week, and pullet growth was recorded. The energy needs for maintenance and body weight gain under a feed restriction regimen was calculated using a model based on metabolic body weight and weight gain described by Hurwitz and coworkers. Average daily body weight gain for the entire experimental period was 13.7 g; the daily energy intake increased with age from 114 kcal/day at 3 wk of age to approximately 270 kcal/day at 20 wk. The estimated daily metabolizable energy requirement for maintenance was 1.57 kcal/g of body weight67 and for growth, .71 kcal/g of body weight. It was concluded that the energy requirement for birds under a feed restriction regimen is considerably lower than those under ad libitum feeding.