Nos. 618-619] EGG PRODUCTION 317 



indefinite amount of inbreeding. Under such circum- 

 stances there would be a tendency for the fecundity 

 factors to remain in about the proportions in which they 

 started. We may, therefore, expect to find ready-made 

 flocks of high producers, true mediocre producers, or 

 even zero producers as well as those containing- the sev- 

 eral types. Thus, the original Barred Plymouth Rocks 

 of the Maine Station contained all three types, while the 

 Cornish contain only true mediocre and zero producers. 



In spite of the fact that we have as yet been unable to 

 apply Pearl's theory of egg production bodily to our 

 Rhode Island Reds (although it may yet be possible to 

 use it after making some modifications) there is no ques- 

 tion but that the ability to lay is inherited, as shown by a 

 better egg production in some families than in others. It 

 is clear also that some males produce offspring that on 

 the whole make much better records than those from 

 other males when the two groups of females with which 

 they are mated are very similar in their winter egg pro- 

 duction. In one instance, the difference between two sets 

 of offspring by two males was clearly due to a difference 

 in maturity. It seems clear, moreover, that some of the 

 internal factors, such as broodiness and maturity, segre- 

 gate independently. 



Summary 



1. The object of the present paper is to present a sur 

 vey of the problem of egg production based on the re- 

 sults of four years' study of egg production in Rhode 

 Island Reds. The presentation of the data is incidental 

 to this object. 



2. On account of disturbing factors, data from two 

 years only is presented. 



3. There are two main conclusions: First: egg pro- 

 duction in our strain of Rhode Island Reds differs in 

 several important respects from Pearl's strain of Barred 

 Plymouth Rocks and also from Leghorns. Second: the 

 egg record of a hen by itself is an unsafe basis on which 



