Effects of short fasting periods and recovery diet protein level on molting response and postmolt productivity in aged laying hens

This study evaluated the effects of short fasting periods and recovery diet protein levels (CP) on molt response and postmolt productivity in 384 aged Hy-Line laying hens over a 19-week period. A 2 × 3 factorial design was implemented, with two molting procedures (2- or 4-day feed withdrawal followed by corn diet) and three resting diets differing in CP content (15.5 %, 11.62 %, or 8.5 %). Positive (non-molted) and negative (conventional fasted molt) control groups were included for comparison. Egg production (EP) declined rapidly within 3-5 days following molt induction across all experimental groups; however, no significant differences were detected among treatments (P > 0.05). Feed intake (FI) during the molting period was not influenced by the molting procedure or resting diet; however, all factorial treatments differed significantly from the control groups (P = 0.001). The applied molting strategies induced moderate body weight losses (6.2-13.7 %), lower than the 26.23 % loss observed in the negative control (P = 0.001). During the 5-19-week postmolt period, EP, FI, feed conversion ratio, egg mass, egg weight, and peak EP were not significantly affected by molting procedure or resting diet (P > 0.05). Hens subjected to a 4-day feed withdrawal exhibited superior albumen quality during early recovery (P = 0.008), whereas differences in yolk and shell traits were temporary and disappeared at later sampling points (P > 0.05). Overall, the results demonstrate that short fasting periods combined with recovery diets of varying CP levels effectively induce molt and support postmolt productivity in aged laying hens, providing a practical and welfare-oriented alternative to conventional molting programs.