Abstract
The results of two similar experiments, each using 204 pullets in cages, are presented. In each experiment, a type of light commercial hybrid, heavier commercial hybrids and Brown Leghorn×Light Sussex cross‐breds were compared, in factorial design, on diets containing either 65 per cent barley, 55 per cent maize or 35 per cent oats and 15 per cent bran. Individual records of egg production, egg weight, food conversion and body weight were kept for eight 28‐day periods, starting when the pullets were in full production. There were no significant differences in egg production between diets but in both experiments a significantly improved food conversion ratio was obtained on the high maize diets, which also gave the highest level of energy consumption. Most breed differences were not significant but in Experiment 1 the crossbreds produced significantly fewer eggs than the hybrids and in Experiment 2 the light hybrids gave a significantly better food conversion ratio than the two heavier types. The crossbred pullets consumed the most energy in both experiments and in Experiment 1 had significantly the worst energetic efficiency of egg production. There were no significant interactions between type of pullet and type of diet in either experiment. Thus there were no indications that, at the energy levels investigated, favourable effects may be expected from the feeding of higher energy diets to the lighter hybrid type pullet. The practical significance of feeding a high barley diet is discussed.