Evaluation of non-feed removal induced molting in laying hens

This study aimed to evaluate the effects of a molt diet on molt induction and the post-molt performance of laying hens. White Leghorn hens (age, 62 wk) were randomly divided into three groups (two experimental, one control). After a 4-wk preliminary period, one group (control) was continuously fed a corn-soybean-based layer ration ad libitum. Molting was induced in the other groups by starvation (MS) or with feed (MF). In the MS group, the feed was withdrawn for 2 wk; this was followed by feeding of a layer ration on alternate days for 1 wk and then ad libitum. The MF group was fed ad libitum a low-protein and low-energy diet based on corn, wheat bran, and corn gluten feed for 4 wk; this was followed by ad libitum feeding of a layer ration. Egg production, egg quality, and feed intakes were measured throughout the experimental period; ovary and oviduct weights and heterophil: lymphocyte (H:L) ratios were measured during molting. During molting, the feed intake in the MF group was lower than that of the control; body weights of the molted groups were significantly reduced. Additionally, the MS group totally ceased egg production within 8 d; in the MF group, egg production decreased to 3.8% by d 10. On d 10 of molting, the H:L ratio of the MF group was lower than that of the MS group. On d 14, the ovaries and oviducts of the molted groups were distinctly lighter than those of the control. Throughout the post-molt period, egg production and egg shell thickness of the molted groups improved; but there were no significant differences. Additionally, the eggs of the MF group were heavier than those of the MS and control groups. This study suggests that feeding of a low-protein and low-energy diet effectively induces molting and increases post-molt production.