STUDY OF SELECTIONS FOR SIZE, SHAPE, AND COLOR OF HENS' EGGS 201 



all incubated eggs were individually pedigreed after 1911. For the 1912 

 and 1913 hatches, the compartments of the pedigree trays were made 

 small enough to hold just one egg, and thus it was possible to know from 

 which egg each chick hatched. In the 1914 hatch and after that time, 

 the chicks were satisfactorily hatched in cloth bags. 



The day-old chicks were weighed on the same direct-reading egg scales 

 as were used for the eggs. After this first weighing the chicks were 

 individually weighed every four weeks on a special type of milk balance, 

 by which the weights could be accurately estimated to 1/100 pound. 

 When these weights were transformed to grams, as was done for some 

 of the correlation tables, the calculation was made by means of the formula, 

 1 pound = 453.6 grams. In the early part of the work a separate record 

 was made of the vigor of the chicks. 



SHAPE CHARACTER 



The basis for selecting eggs for shape was the index figure obtained 

 by dividing the greatest width of the egg by its greatest length and 



FlG. 8. SPECIALLY DESIGNED RATCHET MICROMETERS HELD 

 BY WOODWORKING CLAMP, FOR EGG MEASUREMENTS 



multiplying the result by 100. The measurements were made by specially 

 constructed ratchet micrometers with a J-inch face (fig. 8). 5 One 

 micrometer was adjusted for the egg length and one for the egg width. 



5 These were manufactured by Brown & Sharpe, Providence, Rhode Island. 



