The Influence of Yeast Upon Fertility 

 and Hatchability of Hens' Eggs* 



There is probably no one question, the solution of which is more essen- 

 tial to satisfactory progress in the poultry industry today than that of 

 increasing the fertility and hatchability of hens' eggs. 



THE FERTILITY PROBLEM 



Careful observations made over long periods of years by poultry re- 

 search workers at our various agricultural colleges and experiment sta- 

 tions and by thousands of commercial poultry men who hatch exten- 

 sively, have established the undisputed fact that fertility of hatching 

 eggs is influenced by seasons of the year, by breed, by age of birds, and 

 by general feeding and managerial conditions. Poor fertility creates a 

 big economic question by virtue of the loss resulting from infertile eggs 

 placed in incubators. To the commercial poultry man producing baby 

 chicks on an extensive basis the fertility problem is especially acute for 

 in the course of a season the success of his business is going to depend 

 upon the efficiency of his hatching operations. Poor fertility cuts down 

 the hatches and hence the profits very materially. 



To the breeder of exhibition standard bred poultry the problem is of 

 just as great significance. To the farm poultry raiser the question is not 

 as acute because under farm conditions chicks are hatched later in the 

 season when normal fertility is at its best, but even under these ideal 

 conditions, it is a factor in his success with the hens. 



It has been said by many poultry authorities that poultry-keeping to 

 be successful involves, first of all, the efficient reproduction of the flock. 

 This becomes a very important factor with poultry because of their rela- 

 tively short life, which means that large numbers of young must be 

 hatched and reared each year to replace the older hens which have 

 passed their prime as egg producers. 



Season influences fertility in the following manner : the spring months 

 are the normal reproduction period for poultry. It is during April and 



*These experiments were planned by Prof. Harry R. Lewis, formerly Professor of Poultry 

 Husbandry, New Jersey State University, and conducted at Lewis Farms at Davisville, 

 Rhode Island, under his personal supervision. 



