INDUCED MOLT INCREASES EGGSHELL QUALITY AND CALBINDIN-D28K CONTENT OF EGGSHELL GLAND AND DUODENUM OF AGING HENS

Aged laying hens, which were induced to molt by fasting to a 30% loss of their original body weight or by administration of a diet containing 2% zinc as zinc oxide, experienced reproductive involution and cessation of egg production. Both of the molting treatments resulted in improvement of eggshell density by time of oviposition of the 10th egg after the return to egg production postmolt. Both molting treatments significantly increased the amount of calbindin in the shell gland and duodenum of molted hens as compared with control hens at the 10th egg after return to egg production postmolt.