Progesterone-Induced Unseasonable Molt in Single Comb White Leghorn Pullets

Abstract

THE process of molting has long been of interest to poultrymen chiefly because of its incompatibility with egg production. The fact that the best producers are usually the latest to molt is of particular importance to breeders because these hens are often not in egg production for the earlier hatches of the hatching season. Various methods of forced molting usually involving a drastic change of management, i.e., limiting feed, or light, or withholding water have long been used. These methods are not usually effective on all birds and generally result in loss in body weight during the molting period following the change of management. Numerous workers have demonstrated that molting can be produced by hypophysectomy (Mitschell, 1929; Hill, Corkill and Parkes, 1934) and by the administration of thyroid by feeding (Van der Meuhlen, 1939). Further evidence that the thyroid is involved in molting has been reported by Glazener and Jull …