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This experiment was conducted to determine the effects of molt-induction period on molting and post-molt performance of laying hens. White Leghorn hens at 64 weeks of age were used. After a 4-week preliminary period, they were divided into 5 groups (1 control and 4 treatment groups). The control-group hens were continuously fed a corn- and soybean-based layer ration ad libitum. In 1 of the 4 treatment groups, molting was induced by starvation for 2 weeks (MS group), and in the 3 others by ad libitum feeding of a molt diet (ME: 1.6Mcal/kg) based on rice hull, corn, wheat bran, and corn gluten feed for 2 (MF-2 group), 3 (MF-3 group), and 4 weeks (MF-4 group). During the post-molt production period, the hens were again fed the layer ration. During the molt-induction period, the heterophil: lymphocyte (H: L) ratio, the ovary and oviduct weight, and the energy intake were measured. Egg production, egg quality, body weight, and feed intake were measured throughout the experiment. During the treatment period, compared to the control group, the feed intake and body weight in the molted groups were significantly lower; the ovaries and oviducts of the hens in the molted groups were distinctly lighter (P < 0.01). On day 10 of molting, the H: L ratio in the MF groups was lower than that in the MS group. Additionally, egg production completely ceased within 6 d in the MS group and decreased to 3% at week 2 in the MF groups. No significant differences with regard to days required to regain 50% egg production were found between the MS and MF-3 groups. During the post-molt period, egg production and quality improved in the molted groups, the production in the MF-3 group was highest. We assume that ad libitum feeding of the molt diet for 3 weeks effectively induces molting and enhances post-molt production.

This study investigated the suitable metabolizable energy (ME) level of molt diet for hens that cease producing eggs without being subjected to great stress. During the preliminary period, White Leghorn hens were fed a corn-soybean meal-based layer ration ad libitum. After a 4-wk preliminary period, the hens were randomly divided into 3 treatment groups and 1 control group; the control group was persistently fed the layer ration. The 3 treatment groups were fed the following diets ad libitum for 4wk: (1) 100% molt diet based on corn, wheat bran, and corn gluten feed (ME 2.3Mcal/kg M100:); (2) 85% molt diet with 15% rice hull (ME 1.9Mcal/kg M85:); and (3) 70% molt diet with 30% rice hull (ME 1.6Mcal/kg M70:). During the post-molt period, the hens were returned to the layer ration. During the molting period, the heterophil: lymphocyte (H:L) ratio, ovary and oviduct weights, and MEn intake were measured. Egg production, egg weight, egg quality, body weight, and feed intake were measured throughout the experiment. During the molting period, the feed intake, body weight, and ovary and oviduct weights in the molted groups were significantly (P

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, 62wk) 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 2wk; this was followed by feeding of a layer ration on alternate days for 1wk 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 4wk; 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.