Influence of Starting Rations upon Subsequent Growth

SEVERAL studies, reviewed by Roberts and Carrick (1935), show that during the first 8 to 12 weeks the growth rate increases as the level of protein in the ration is increased, at least up to a level of 18 to 20 percent of protein. These authors found that chicks fed for the first 4 weeks on relatively high protein rations may then be changed to rations with lower protein content without making important differences in the rate of growth, feed efficiency, or viability of the chicks from 4 to 12 weeks. Several more recent studies agree that relatively high levels of protein feeds are necessary to promote rapid growth at the start, but different workers do not agree as to how long chicks should be continued on a high protein level. McConachie et al. (1935) concluded that the optimum protein content for growth in chicks during the first 6 weeks . . .