Compensatory Growth and Sexual Maturity in Broiler Females Reared Under Severe Food Restriction From Day Of Hatching

1. Compensatory growth and the onset of lay were studied in White Rock broiler females severely restricted in food intake from day of hatching. 2. When changed to feeding ad libitum the restricted birds gained weight rapidly, but stabilised at a mean body weight 500 to 700 g less than that of controls fed ad libitum. Egg production was similar to that of controls. 3. Birds maintained at low mean body weight (2 224 g at 42 weeks) by continued restriction did not come into lay. In groups maintained at somewhat higher mean body weights (2 300 to 2 700 g) for periods of up to a year, some birds came into lay. 4. Birds fed ad libitum showed accelerated development of comb, ovary and oviduct and weighed 2 300 to 2 700 g between 14 and 15 weeks of age, but did not come into lay until 20.5 weeks of age. 5. These results suggest that a minimum body weight and age may be required for the onset of lay in this strain.