FERTILITY AND HATCHING OF EGGS. " I39 



present statistics, on the average a bird whose eggs run high in 

 fertiHty in the pullet year is as likely as not to produce eggs 

 running low in fertility in the second year, and vice versa. 

 This result is independent of the fact that the birds were with 

 cockerels of generally equal breeding ability in the two years, 

 as shown by their pen averages. 



4. There is a significant positive correlation between the per- 

 centage of fertile eggs hatched from the same group of birds in 

 two successive breeding years. The coefficient here (0.331) is 

 4 times its probable error. This result means that in the long 

 run the bird whose fertile eggs give high percentage hatches in 

 the pullet year, will show the same characteristics in her second 

 breeding year. And similarly the bird whose fertile eggs hatch 

 poorly in her pullet year will on the average, make the same 

 kind of a record in her second year. This result emphasizes 

 the importance of a carefully kept hatching record when one 

 is saving pullets for the next year's breeding work or to furnish 

 eggs to sell for hatching. 



Are the Fertility and Hatching Quality of Eggs 

 Inherited Characters? 



In this section we shall undertake the discussion of a very 

 interesting and, at the same time difficult point. Theoret- 

 ically it is a simple matter to determine whether the two char- 

 acters, fertility and hatching quality of eggs, are inherited. If 

 the question be put in this form : "Will the daughters of a hen 

 whose eggs are above the average (for mothers) in percentage 

 fertility produce eggs which will in turn be above the average 

 (for daughters) in fertility?" it is at once apparent that the 

 necessary procedure is to form a correlation'table in which one 

 variable is the percentage fertility of the mother's eggs and the 

 other the percentage fertility of the daughters' eggs. The corre- 

 lation coefficient determined from such a table should then be 

 a measure of the degree to which this character is inherited 

 from mother to daughter. The same line of reasoning and 

 treatment of the data is also to be adopted to determine whether 

 the hatching quality of eggs is inherited from mother to 

 daughter. While the, problem is thus theoretically simple, 

 actually there are a number of difficulties as will presently 

 appear. 



