Dietary zinc as an effective resting agent for the laying hen

Abstract

Three experiments were conducted, with White Leghorn laying hens, to compare a conventional molt procedure with the use of zinc as an effective resting agent. In experiment one a molting and resting method were compared. Method one was a conventional molt procedure which employed no artificial light for ten days, no water for twenty-four hours, and feed was removed for ten days. Method two was a resting procedure which consisted of adding 20,000 ppm. of zinc (as zinc oxide) to the laying hen diet, employing no artificial light for ten days, and water was supplied ad libitum. The zinc diet was fed for 4, 6, 8, 12, or 16 consecutive days. Egg production ceased within five days for the zinc fed birds, while requiring eight days for the conventional molt procedure to cease egg production. A smaller decline in per cent shell and specific gravity were noted during this period for the eggs laid by the zinc treatments, when compared to the conventional molt procedure. In the treatments receiving the zinc diet for 12 days or less a level of 50% egg production was attained sixteen clays before the conventional molt procedure did. Feeding the zinc diet for sixteen days resulted in subsequent inferior egg production for the duration of the experiment. Feeding the zinc diets for less than 12 days resulted in a significant increase in egg production, when compared to the conventional molt procedure. Zinc analysis of the egg yolk and albumen resulted in no significant differences between treatments..