STUDY OF SELECTIONS FOR SIZE, SHAPE, AND COLOR OF HENS' EGGS 255 



TABLE 58. PERCENTAGE OP EACH YEAR'S FLOCK BEGINNING TO LAY IN THE RESPECTIVE 

 MONTHS FROM NOVEMBER TO JUNE, INCLUSIVE 



Size character 



The variations in the mean size of the eggs produced during the successive 

 months by the size-selection birds are shown in figures 28 to 31. These 

 curves are made up by calculating the mean for the first month's pro- 

 duction of the first year, the second month's production of the first year, 

 and so on for the succeeding months and years for each hen used, 

 and then finding the mean for all available hens at each period. Data 

 for eleven months of each year were available for a sufficient number 

 of birds to make the figures reasonably reliable. 



The size of the eggs produced by pullets increases fairly regularly 

 during the year, but no real increase in the size of the eggs produced during 

 the later j^ears of production can be observed. It may seem that this 

 statement is disproved by figure 30, but a glance at figure 28 shows that 

 the size of the first year's production increases so rapidly that it causes 

 the mean size to increase slightly. 



All seasonal effects are eliminated in these studies, the birds being 

 arranged in accordance with the month when they began laying each 

 year, irrespective of the particular month which that happened to be. It 

 would seem that the wide fluctuations after the ninth month in figure 28, 

 and after the seventh month in figure 29, may be due to the fact that too 

 few birds were available for study; but an apparent tendency for the size 

 of the egg to increase rapidly near the end of the laying season is observed. 



