THE MAMMOTH INCXTBATOR AND BROODER 



433 



keep the pores open and allow rapid diffusion. It has been 

 estimated that the required amount of fresh air is one cubic 

 foot per egg per hour. A chamber containing 200 eggs would 

 require 20 cubic feet of air to pass through it per hour. This 

 would be a complete change of all air in the compartment 

 three times during the hour. 



The light must be higher at the start to secure the right 

 temperature in the egg chamber. The embryo in the egg 

 respires giving off moisture and CO2. If the moisture of the 

 chamber is too low the shell membranes become too dry and 

 the chicks have trouble getting out of the shell, or even die in 

 the shell. The humidity must be constant. 



The amount of heat needed over any 600 eggs at different 

 cellar temperatures, as given by the Candee Incubator Co., is 

 as follows : 



Cellar 

 temperature 



Square feet of radiation 

 required to secure 103° 



Zero 2 . 94 square feet. 



10 above. 



20 



30 

 140 

 145 

 150 



65 



60 



2.655 



2.151 



1.702 



1.29 



1.072 



0.858 



642 



0.429 



When the cellar temperature rises from 40° to 60° F. — only 

 20° F. — only one-third as much heat is required; and as the 

 cellar gets warmer, less is required. 



The thermometer bulb should be kept at the top of the eggs. 

 Some recent investigational work rather points to the fact that 

 the better hatches are obtained where the temperature is kept 

 during the entire three weeks at 103° F. 



Effect of Humidity. — The hygrometer is an instrument 

 with which we can tell just how much moisture there is in a 

 machine. It is found that to obtain the best hatches there 

 should be 60 per cent, moisture in the air that passes through 

 the machine, 55 per cent, the second week, and 50 per cent, 

 tapering down to 45 per cent, by the end of the third week. 



^ Normal cellar temperature. 

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