CHAPTER VI 



THE NECESSITY OF AIR AND HOW TO VENTILATE 

 THE POULTRY HOUSE 



Note to Teacher : Visit a properly ventilated house and one not 

 properly ventilated. 



81. Oxygen of the Air. Air contains an element called oxygen. 

 Oxygen is essential, for if air is withheld from the bird for a 

 very few moments it will die. 



82. How the Bird Obtains Oxygen. The bird obtains oxygen 

 by breathing air into the lungs. The air passes through the 

 nostrils, windpipe (trachea), lungs, and into the bladder-like 

 structures extending from the lungs, called air sacs. 



83. How the Oxygen Is Taken Up. The lungs and air sacs 

 are lined with minute blood vessels in which blood circulates 

 and takes up the oxygen from the air, carrying it to the tissues 

 of the body where it is needed to maintain life. 



84. Carbon Dioxide from the Body. In the performance of 

 the vital processes within the body of the fowl, there is formed 

 a poisonous gas called carbon dioxide. This carbon dioxide 

 must be got rid of or the bird will die. 



85. How Carbon Dioxide Is Got Rid Of. The blood absorbs 

 the carbon dioxide and carries it to the lungs, where it is given 

 off to the air. Thus the breathing in of air furnishes oxygen 

 and the breathing out of air eliminates the carbon dioxide. 



86. Ventilation Required in Poultry Houses. Poultry houses 

 must be properly .ventilated, so that a fresh supply of air will 

 be always present and sunshine can find its way into the house. 



87. Methods of Ventilation. There are two methods of venti- 

 lation : ventilation by diffusion and ventilation by draft. 



88. Ventilation by Diffusion. Fig. 17 shows an open- front 



