Effects of moderate energy restriction on light and medium hybrid laying hens

Abstract

1. Two light and two medium hybrid strains were fed, from 32 to 48 and from 56 to 68 weeks of age, ad libitum or approximately 89%, 85% and 80% of the ad libitum intake; from 48 to 56 weeks all the birds were fed ad libitum.

2. A daily energy restriction of 11 to 13% in the first period, resulted in the rate of lay being depressed by nearly 11% points for one light hybrid strain and by more than 5% points for the medium hybrids while the corresponding depressions in egg weight were 4% and 2%.

3. During rehabilitation egg output was similar for controls and restriction treatments, though that of the most severely restricted groups remained slightly depressed.

4. Energy restriction of about 8% during the second period depressed rate of lay by about 3% points and egg weight by about 2%.