MAINE AGRICULTURAL EXPERIMENT STATION. I914. II 



American breeds is colored by a particular kind of yellow fatty 

 pigment known as a lipochrome pigment. While the matter 

 has not yet been completely investigated it is very probable that 

 the yellow color of chicken fat which gives the color to the skin 

 is due to the same pigment which gives the yellow color to the 

 milk of the Jersey or the Guernsey cow. Recent experiments 

 on the color of milk in cattle have demonstrated that there this 

 pigment is chemically precisely the same as that which gives 

 the yellow color to the common carrot. This coloring matter is 

 known by the name carotin. In the white skinned breeds of 

 poultry this yellow pigment is very nearly, or completely, absent, 

 with the result that while the skin fat is there just as in the 

 yellow skinned breeds it is not colored. Also probably this 

 same coloring matter gives the yellow color to the yolk of the 



This last consideration is one which calls attention to the 

 practical bearing of these results on shank color. It is a well 

 established fact, both in cattle and in poultry, that when the 

 food does not supply a sufficient amount of this yellow coloring 

 matter carotin for the product, whether milk or eggs, the animal 

 then draws on its own body fat for the further supply of this 

 coloring matter. This results in a bleaching of the body fat 

 of its yellow color while keeping up the color of the milk or the 

 eggs. From this fact it results that the general skin color, and 

 particularly the shank color, of a hen having naturally yellow 

 shanks is much bleached out after the hen has been laying 

 heavily, and furthermore, the heavier the laying has been the 

 greater will be the amount of bleaching observed. In conse- 

 quence of this it is possible to go through a flock at the end of a 

 laying year and pick out at once by the color of the shanks 

 those birds which have been extremely heavy layers from 

 those which have been drones. The drones will be the birds 

 which at the end of the season have bright yellow legs, such as 

 one is accustomed to see in pullets which have not yet begun to 

 lay. On the other hand, birds which have done a hard year's 

 work and produced many eggs will have shanks completely 

 white or nearly so. Examination at this Station of many hun- 

 dreds of birds, whose trap nest records are known, makes it 

 possible to say positively that no bird which has been a high 



