208 EARL W. BENJAMIN 



These methods of selection explain why so few records are actually 

 available for the study of some of the characters. 



In following the method of individual mating, each male to be mated 

 with any females in the pen is retained in a coop. Whenever a female 

 is removed from the trap nest, the attendant finds her band number 

 on a posted list and learns the band number of the male with which she 

 is to be mated. Before placing her in the mating coop, however, the 

 work is further checked by looking for the hen number on a tag attached 

 to the coop, and also by comparing the color of her band with the color 

 of the male's band. The female is then placed in the coop and removed 

 at the time of the next inspection of the trap nests. Usually about twelve 

 mating coops were needed in each house. 



Every egg laid by the mature birds is recorded as to either its size, 

 its shape, or its color, in the same way as the original incubated eggs 

 were recorded. This enables the investigator to compare the character 

 of the egg incubated with the eggs which the resulting pullet produces. 

 Many of the eggs from hens in the size and shape selections were also 

 photographed, as previously explained. 



RESULTS 



The results of the investigation may properly be grouped into those 

 concerned with the inheritance studies and those concerned with other 

 related studies, the former being dealt with first. 



INHERITANCE STUDIES 



Variability of production due to differences between the parent types 



An effort was made to determine to what extent the variability of a bird's 

 production was dependent on the differences existing, for the particular 

 character, in the respective dam and sire. The studies made in this regard 

 are illustrated in tables 1 to 12, and a summary is given in table 13. In 

 constructing these tables, the standard deviations for each of the three 

 egg characters considered, for each respective year's production, were calcu- 

 lated, and these were correlated with the differences existing between the 

 means of the respective egg character for all the eggs produced during the 

 life of the respective dam, and as calculated for the respective sire. 9 



9 The life mean for the sire was obtained by averaging his respective dam and sire. The character of 

 the egg from which the first sires used in the study were hatched, was taken as the mean for these first sires. 



When a class is designated by one figure, that figure represents the upper limit of the class; when a class 

 is designated by two figures, the upper figure is included in the class. 



