CORRELATION BETWEEN EGG-LAYING ACTIV- 

 ITY AND YELLOW PIGMENT IN THE 

 DOMESTIC FOWL 1 



Dr. A. F. BLAKESLEE and D. E. WARNER 



So far as the presence of visible yellow pigment is con- 

 cerned, there are two groups of domestic fowls. In the 

 first group, represented by the Orpington breed, yellow is 

 constantly absent from legs, beak and body fat. In the 

 second group, represented by the Leghorns and the so- 

 called American breeds, such as the Plymouth Rocks, 

 Wyandottes and Rhode Island Reds, yellow, in the form 

 of yellow fat, 2 is present in varying amounts in the parts 

 mentioned. In this latter group, individual birds may 

 undergo considerable change in the amount of the yellow 

 pigment visible. The standard of the show-room, how- 

 ever, demands yellow in the legs and beak in these breeds 

 and, in consequence, birds that have become pale in these 

 parts are liable to be scored down by the professional 

 poultry judge. The paling or yellowing of the legs in the 

 breeds mentioned has been attributed by poultrymen to 

 various environmental factors. Thus, good health and 

 vitality, abundance of range and exercise, proper food 

 such as meat, corn, gluten meal and " green food " are 

 said to increase the amount of yellow pigment, while poor 

 health, moulting, confinement with insufficient exercise, 

 running on sandy soil and in mud, as well as climate and 

 the mere aging of the bird, are held to be responsible for 

 the paling of the legs in these varieties. 



Of recent years, some individual poultrymen have 

 claimed that paling of the legs is due to heavy laying. 

 This view has been maintained by J. E. Rice. 3 Mr. Tom 

 Barron, 4 one of the most successful of the English poul- 

 trymen, in an address before the Connecticut Poultry 



1 Paper presented in brief before the American Society of Naturalists, 

 Phiknlrlphia, December 31, 1914. 



2 Barrows, H R., "Histological Basis of Shank Colors in Domestic Fowl." 

 Bull. 232, Maine Agric. Exper. Station, 1914. 



3 Circular 54, X. Y. State Dept. of Agriculture, 1912. 

 * Connecticut Farmer, September 12, 1914. 



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