202 



POULTRY PRODUCTION 



both back and forth in water that is 103° to 105° F. in tem- 

 perature. 



Moisture Pans. — Shallow pans about the size of the egg 

 trays, in which wet sand may be placed for the purpose of 

 furnishing moisture for the eggs, should be a part of the 

 equipment of every incubator used in any but very moist 

 climates (see Fig. 99 at L and 101). 



Fig. 102 



An egg tester. 



Egg Testers. — An egg tester is an arrangement for trans- 

 mitting light through an egg for the purpose of discovering 

 whether the embryo is alive and growing. There are many 

 styles of testers, but all work upon the principle of shutting 

 all light from the eye except that which passes through 

 the egg. 



The most common type, shown in Fig. 102, is a metal 

 chimney placed on the incubator lamp. A hole in the side 



