Effects of short term feed restriction on development of body weight, egg number and egg weight in laying hens

In the present study the effect of a short term feed restriction in laying hens (gallus gallus dom.) on egg laying performance and egg quality was investigated with emphasis on timing and intensity of changes in these traits following controlled body weight changes. Three trials were carried out and a total of 1026 laying hens (Lohmann Selected Leghorn = LSL and Lohmann Brown = LBJ were used. The layers were equally separated in groups according to age at the beginning of the feed restriction (32, 44 and 56 wk of age) and amount of feed given; The control group was fed ad libitum whereas two groups received 10% less (i.e. about 110 g/hen d) and 15% less (i.e. about 100 g/hen d) respectively compared to the feed intake of the respective group during the last 14 days before feed restriction began. The duration of the short term feed restriction was 8 weeks. A standard layer mash was given to all hens. Before, during and after the treatment up to 80 weeks of age body weight, laying intensity and egg weight were recorded. In order to compare the intensity of the changes in various traits following feed restriction, data were standardized by transformation and were corrected for natural age related development of the traits. Comparing standardized values the reduction in laying intensity was distinctly larger than the simultaneous reduction in body weight, whereas egg weight was less affected. Ln contrast age of the hens at the onset of feed restriction had no significant effect on the traits under investigation during the shea term feed restriction period. During the following acl libitum feeding period performance depressions resulting from restricted feeding were compensated. Compared to the control group laying intensity up to 80 weeks of age was improved when feed restriction was applied at 32 weeks of age. Furthermore short term feed restriction tended to increase egg weight, being more pronounced when the treatment started at a higher age of the hens. In adjustment to market requirements a short term feed restriction for laying hens can be applied without negative effects on total performance during the laying period, as long as the remaining duration of the laying period after finishing the restricted feeding period is sufficient to use compensatory effects. For hybrid laying hens, representing the present state of breeding, general restricted feeding for a longer period is not recommended.