An Inborn Characteristic Determining the Response of Chickens to a Diet Free of Animal Protein

Publisher Website
Google Scholar
Abstract
Examination of the individual hatchability records of 183 hens which had been fed a diet containing no animal protein for a period of 11 lunar months revealed that 44% of the hens showed hatchability figures between 0 and 70%, 37% showed from 70 to 85% hatchability, and 19% showed from 85 to 100% hatchability. Further investigation revealed that the high hatchability maintained by the minority could not be explained on the basis of coprophagy, storage of the essential factor, or adaptation to an unfavorable diet. Hens characterized by high and by low hatchability were not found to vary with respect to the growth promoting properties of their excreta or with respect to their efficiency of feed utilization. The progeny of hens characterized by high, intermediate, and low hatchability, respectively, showed high, intermediate, and low viability and growth rate to 6 weeks of age. The effect of dietary supplements upon the growth of chickens varied with the maternal diets and with the ability of the dams to withstand dietary deficiency. This variation may be of considerable importance, especially in experiments in which the diets are variable because of their content of natural feedstuffs. The variability among the hens is believed to have been inborn, as that of their progeny certainly was. Whether the variation of the progeny was congenital or hereditary cannot be stated on the basis of present evidence.