A STUDY OF SELECTIONS FOR THE SIZE, SHAPE, AND COLOR 



OF HENS' EGGS 1 



E!AKL W. BENJAMIN 



The study here reported was conducted from the spring of 1911 until 

 1919, with the purpose of determining the results that may be obtained 

 by selecting the breeding stock of the domestic fowl, and the eggs for 

 hatching, in order to change the size, shape, and color of the eggs pro- 

 duced by the offspring. There is a certain type of egg which especially 

 meets the desires of the respective customers in various markets. It is 

 usually not practicable to grade the eggs closely, and it becomes necessary 

 to select and develop the flocks so that the proportion of eggs unsatis- 

 factory to the customer may be reduced to the minimum. 



The wholesale trade of the New York City market requires the size 

 and shape of the eggs to be such that the eggs are not crowded, but fit 

 snugly, in the fillers of the commercial thirty-dozen cases; this means 

 an egg about 2f inches long and If inches wide, and usually weighing 

 from 2 to 2| ounces when fresh. Shipping only the eggs of proper size 

 and shape insures less breakage, better appearance, and a resulting higher 

 sale value. The New York City market has a special demand for white- 

 shell eggs and will sometimes pay from eighteen to twenty cents a dozen 

 more for eggs having chalk-white shells than for those varying from cream- 

 tinted to brown. 



REVIEW OF LITERATURE 



The study of the external characters of eggs seems to date from a com- 

 paratively recent period, and even at the present time the published 

 data with respect to these characters are very meager. 



Tradition tells us (in Horace, Lib. II, st. 4) that the eggs of pullets 

 are longer than those of hens, and that pullets' eggs produce a larger 

 proportion of male chicks than do hens' eggs. This tradition has been 

 developed until many persons believe that long eggs produce cockerels 

 and round eggs produce pullets when incubated. 



1 This study completes the work reported in part in a thesis presented by the writer to Cornell Uni- 

 versity in 1912 for the degree of master of science in agriculture, and continued in a thesis presented to 

 Cornell University in 1914 in partial fulfillment of the requirements for the degree of doctor of philosophy. 



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