Loss of Weight of Hen’s Eggs During Incubation Under Different Conditions of Humidity and Temperature

THE progressive loss of weight of eggs during incubation has been known since the eighteenth century when Reaumer (1750) made his noteworthy studies on incubating eggs. Since that time many investigators have studied this phenomenon. The many studies have proved that the chief source of weight loss is due to evaporation of water which depends on the relative vapor pressure inside and outside of the shell of the incubating egg. As the conditions inside the shell are practically constant, the loss of weight depends upon the vapor pressure in the environment of the egg which is controlled principally by temperature and humidity. In early work no attempt was made to determine the humidity of the air surrounding the eggs, consequently the loss of weight reported varied greatly, ranging from 9 to 20 percent for 20 days. Later investigators attempted to measure the humidity in the incubator while ascertaining the loss . . .