Sexual Maturity and Body Changes in Layer Type Hens؛

Abstract

The growth of organs and tissues in the laying fowl were studied from 4 to 76 weeks of age. A marked increase in the weight of the sexual organs began at the beginning of pu-bertal growth. During the period of their rapid growth there was little change in the growth of skeletal muscle and the liver, but there was an increase in bone mass, liver fat and body fat. The onset of pubertal growth was associated with an increase in the amount of body calcium and phosphorus. However, by the time the bird entered the laying period a fall in calcium and phosphorus occurred. Breast muscle increased in weight during the pubertal growth, but thigh muscle weight remained unchanged. Both muscles however decreased in size during the beginning of the laying period.