Performance of male broilers to 70 days when fed diets of varying nutrient density as mash or pellets

Two experiments involved Hubbard Hi-Y male broilers grown to 70 days of age to observe the influence of differing protein levels and energy levels in diets of either pellets or mash. In Experiment 1 low energy (2800-2900 kcal ME/kg) and low-protein (16-18% CP) starter diets caused reduced early growth. Diets with 18% CP and 2900 kcal ME/kg seemed adequate for optimum growth from 21 to 49 days. In the 50 to 70 day finisher period, 16% CP and 2800 ME/kg was adequate for growth. Feeding single-stage 16% CP, 2800 kcal ME/kg throughout rearing resulted in the lowest feed cost/kg live weight. However, this treatment caused loss in breast yield. A single-stage diet for 18% CP, 2900 kcal ME/kg seemed adequate in terms of growth, nutrient utilization, and carcass quality. In a second experiment diets of varying nutrient density were fed as mash or pellets. Broilers fed mash had a dramatically reduced mortality (mean 3.9 vs. 15.3%) associated with reduced growth rate (mean 3.68 vs. 4.13 kg at 70 days). Feed cost per kg live weight marketed favored mash feeding because of associated low mortality. Breast yield of mash-fed birds was less when low nutrient dense (but not high nutrient dense) diets were used.