148 The Hen at Work 



body is lengthwise, with its beak right against the 

 inner membrane of the shell, near the large end. 

 If the eggs are not properly turned while hatching, 

 the chick will have difficulty in making this change, 

 and if its head is not at the right point, it will be 

 unable to free itself from prison. Fully developed, 

 it will die in the shell, because the beak cannot 

 strike fairly against its inner surface. 



Rapidly the embryo grows during the last week, 

 until it fills all the space within the shell except the 

 air cell, which is just above the chicken's head. 

 On the last day the walls of the abdomen close 

 about that part of the yolk not already absorbed, 

 and the chick is ready for its earthly adventures. 



Hatching. — Nothing in poultry life is more 

 interesting than the last hours of the chick within 

 the shell, and his entrance into the new world. 



About the fourteenth day, the embryo turns 

 about in the egg so its head is near the air sack. 

 Thus it grows until it is ready to leave the shell, 

 usually about the twenty-first day. Then it 

 thrusts out its beak, tears away the inner shell 

 membrane, and begins to breathe the air contained 

 in the space at the big end of the egg. 



Now for the first time its lungs fill with air. 



