Pre-laying Nutritional and Environmental Factors in the Performance of the Adult Fowl

FACTORS affecting the calcium and/or phosphorus requirements of the growing chicken female from 8–18 weeks for “normal” development and maximum productive performance and body maintenance during the first egg laying cycle have been given inadequate consideration. Of the numerous pre-laying factors, known or unknown, that may possibly contribute to the variation in response of production bred stock, differences in nutrient intake (“inadequate,” “adequate” or “excessive”) and environmental conditions (housing, temperature, lighting, etc.) are of universal importance. It has been demonstrated that restricting the level of total feed intake during the growing period resulted in delayed sexual maturity and increased egg production which persisted through the second egg laying cycle (Hollands and Gowe, 1961) or third cycle (Fuller and Dunahoo, 1962). That these effects may possibly result from more optimum development of the endocrine system of birds reared on restricted feed has been suggested by Hollands and Gowe (1961). The …