STUDY OF SELECTIONS FOB SIZE, SHAPE, AND COLOR OF HENS' EGGS 199 



The eggs were selected from three-year-old Single Comb White Leghorn 

 hens, and an effort was made to get eggs from hens that consistently laid 

 the type of egg selected. The Single Comb White Leghorn breed was 

 used for the study because, first, it is the commonest breed in New York 

 State, and secondly, because it was desired to study these commercial 

 characters of eggs by the use of commercial breeds, and the Leghorn 

 predominates on commercial egg farms in the United States. The birds 

 used were from the high-producing trap-nested stock of the well-established 

 Cornell strain. 



SIZE CHARACTER 



The basis for selecting eggs for the size character was weight. A Harvard 

 balance, equipped with a slide reading to 10 grams in tenths, was used 

 early in the work, but this was later replaced by a special direct-reading 

 balance (fig. 7). 4 Exact weights were used at first, but later the weights 

 were recorded in 2-gram classes and could be transferred directly for 

 use in the correlation tables. Eggs weighing more than 50 grams and 

 not more than 52 grams were recorded as 51 grams in weight and were 

 grouped in the 50-52-gram class in the correlation tables. 



The eggs were weighed as soon as possible after they were laid, in 

 order to avoid any serious losses due to evaporation. When it was neces- 

 sary to hold them for some time before weighing, they were kept packed 

 and in a cool, rather moist, place. After January, 1913, the eggs were 

 held in an artificially cooled room at a temperature of from 32 to 40 F. 



The eggs selected for incubation each year were weighed, as well as 

 all the eggs produced by any of the hens in the size-character studies. 

 In the early part of the work the eggs selected for incubation were also 

 measured and their length and breadth recorded. 



Just before hatching, the eggs were placed in pedigree trays. The 

 trays used in 1911 were so constructed that it seemed advisable to put 

 into one compartment all the eggs produced by the same hen. If more 

 than one egg in a compartment hatched, it was necessary to use the average 

 of all the hatched eggs in that compartment, in order to calculate the 

 average type of egg which hatched. This gave a fairly accurate result 

 because, as a rule, all the eggs laid by the same hen are of the same general 

 type. However, as this method allowed the possibility of some error, 



4 This balance was imported by Cornelius Kahlen, New York City. 



