Sources of Calcium for Laying Chickens During Hot Weather

Abstract

IT HAS been common knowledge for many years that eggs laid during the hot summer months generally have thinner, more fragile, shells than have those laid during the cool months. The first explanation of this phenomenon that is based on experimental data appeared in the report of Bennion and Warren (1933), who observed that when hens were subjected to high air temperatures their egg shells seemed more fragile. Several years later, Warren and Schnepel (1940), reported that when hens held under controlled air temperatures were subjected to a temperature of 90 degrees F., there was a striking reduction in the thickness of their egg shells. In connection with the latter experiment, Conrad (1939) obtained data showing that the thinning of egg shells under high air temperatures is associated, or at least coincident, with a decrease in the blood calcium level of the laying chicken.Calcium carbonate was used as the .