Control of Flock Uniformity of Broiler Breeder Pullets Through Segregation According to Body Weight

Broiler breeder replacement stock was housed in six floor pens with 100 females and 15 males per pen. All birds were fed an 18% protein starter ration and grown under the same management conditions to 4 weeks of age. At 4 weeks, 300 females were weighed and divided into three groups consisting of the heaviest, middle, and lightest birds. These three groups were designated the treatment flock and were fed 13%, 15%, and 17% protein rations, respectively. The remaining 300 pullets were divided according to body weight in the same manner and fed a 15% protein ration throughout the growing period. These birds were designated as the control flock. Both flocks were fed according to a skip-a-day regimen and provided with 12 hr of light. At 8, 12, and 16 weeks, both flocks were weighed, rearranged according to body weight, and fed the ration appropriate as outlined above. The average body weight of the two flocks at 4, 8, 12, 16, and 20 weeks did not differ from each other by more than 44 g. Both flocks averaged 2.4 kg at 20 weeks of age. The treatment flock exhibited higher degrees of uniformity than the control flock from 8 to 20 weeks of age. The difference in uniformity was attributed to the feeding of a high protein diet to the light birds and a low protein diet to the heavy birds. It was concluded that the method of segregating broiler breeder pullets according to body weight as a part of a restricted feeding program can result in a more uniform flock at 20 weeks of age.