Observations Concerning the Time Factor in Egg Production

Abstract

When a bird lays for several days in succession the first egg is usually the heaviest and generally there is a gradual decrease in the weight of the eggs toward the end of the series, the last egg being the lightest. Then, after the bird has ceased to lay for one or more days, another series of eggs is started beginning with a heavy egg, and so on. A series of eggs so laid is called a cycle. The first egg of a cycle is usually laid relatively early in the day and the remainder of the eggs are generally laid later and later respectively on following days. An example of an egg cycle showing the weights of the eggs and the time of laying is shown in Table I. It is evident from Table I that the normal laying period for this bird during the time under consideration was . . .