172 



POULTRY PRODUCTION 



By the thirteenth day the feathers are distributed over the 

 body. Their color may be seen through the thin walls of the 

 sacs, which inclose them until the nineteenth day. On the 

 thirteenth day the scales and nails appear, and by the 

 sixteenth day are found to be quite firm and horny, as is 

 also the beak. By the sixteenth day the white of the egg 

 has disappeared, and on the nineteenth day what remains 

 of the yolk is drawn into the body cavity. 



Fig. 84 



Embryo chick, forty-eight hours old, with the heart located outside the 

 body. Magnified. (Courtesy of Iowa Experiment Station.) 



When formed the chick is placed in the egg with its head 

 bent forward beneath the right wing and the legs brought up 

 toward the head. The end of the upper maiidible of the beak 

 is equipped with a horny cap which bears a sharp point, and 

 by means of this, while slowly revolving in the shell, the chick 

 is able to press against the shell, chipping it in a circular 



