1 66 PROFITABLE POULTRY PRODUCTION 



studying natural incubation there is, in the first 

 place, top heat. Heat rising from below would 

 never do, as it would evaporate the moisture from 

 the eggs too quickly. The next point is steady 

 warmth ; when a hen is brooding, her temperature 

 is invariable. The temperature of a brooding hen 

 is about 104 degrees, and that does not vary a great 

 deal during the time she is sitting. Therefore, in 

 order to have a successful incubator, a machine 

 capable of developing a top heat of 104 degrees to 

 the eggs and keeping it steady there, is needed. 

 Of course, the eggs under the hen will vary in tem- 

 perature according to the position they take ; that 

 is to say, those under the breast will be rather 

 warmer than those on the outside. But they are 

 changed in position now and again. Each machine 

 must possess a sufficiency of ventilation ; fresh air: 

 is a perpetual necessity. 



MOISTURE ESSENTIAL 



Another very greatly discussed question is that 

 of moisture. Hot-air incubators are usually non-i 

 moisture machines, whereas the tank machines re- 

 quire added moisture. Perhaps there has been no 

 bigger bone of contention between the manufac- 

 turers than this question of moisture or non- 

 moisture. Within reasonable limits, both systems 

 are satisfactory. A great many people overdo the 

 moisture. Some manufacturers even advise that 

 if chicks do not come out freely to dip the eggs in 

 water. That is a ridiculous practice. Eggs do not 

 require a lot of added moisture. The amount that 

 should be passed through the machine should be 

 just about sufficient to keep a check upon the 



