Dietary self-selection and use of reverse-protein diets for developing broiler breeder pullets

Broiler breeder pullets of a commercial strain were allowed a free-choice of diets providing concentrated sources of protein (46.3% CP, 2487 kcal ME/kg) or energy (8.6% CP, 3218 kcal ME/kg). Three replicate floor pen groups of 22 birds each were compared with control birds consuming a regular diet ad lib. Diet self-selection had no effect on growth rate (P greater than .05), while calculation of nutrient intake indicated a dietary equivalent consumed of some 18% CP 0 to 4 weeks, some 13% CP 4 to 16 weeks, and 17% CP from 16 to 20 weeks. This pattern is discussed relative to previous findings with Leghorn pullets. In a second trial birds were fed a reverse protein program, with the following diets being provided ad lib: 0 to 12 weeks, 12% CP, 3080 kcal ME/kg; 12 to 16 weeks, 16% CP, 2974 kcal ME/kg; and 16 to 20 weeks, 19% CP, 2972 kcal ME/kg. Control birds received a regular feeding program, involving a restricted feeding schedule as recommended by the breeding organization. Each diet was tested with six replicate cages of 10 birds each. Up to 8 weeks-of-age reverse protein fed birds were smaller in body size than conventionally restricted birds. However, after this time, the converse was true.