THE TIMING OF FOOD AVAILABILITY AFFECTS GROWTH IN CHICKS

Three experiments challenged the ability of domestic chicks to grow no rmally by differentially restricting when and for how long food was av ailable. In Experiments I and 2, food was available for six 1-hr, thre e 2-hr, two 3-hr, or one 6-hr (a.m., p.m.) periods/day over the first 3 posthatch weeks. Control groups received continuous access to food. In Experiment 3, different amounts of light surrounded the 6-hr feedin g period. In Experiments 2 and 3, chicks composed their own diets from separate sources high in protein or carbohydrate. Except for-the sing le 6-hr meal preceding dark, large meals at other-times of day in?pail ed growth-primarily because chicks consumed insufficient dietary prot ein and ate less earlier in the light phase. We conclude that both the amount eaten and the proportion of the diet consumed as protein at gi ven times of the day ale phylogenetically acquired strategies that fit the omnivorous, diurnal chicken to its niche, independent of its mome ntary requirements, and appear early in development. (C) 1998 John Wil ey & Sons, Inc.