ARTIFICIAL INCUBATION 67 



bator is used, it is advisable to turn the eggs 

 every day. 



It is better to select eggs of a uniform size for 

 each setting, and all other eggs should be discarded. 

 Some breeders even go so far as to advocate setting 

 eggs of only one variety in a machine at a time. 

 This theory may hold good in some cases. For 

 instance, the eggs of Leghorns, coming from vigor- 

 ous stock, will hatch a day sooner than eggs of 

 the heavier breeds. On the other hand, I know 

 of successful hatches in incubators containing both 

 hen and duck eggs. One poultry raiser I know of 

 set a machine with seventy-five hen and forty duck 

 eggs, from which he hatched sixty-eight chicks and 

 thirty-seven ducklings. The duck eggs required 

 four weeks for incubation. They were put into the 

 incubator a week before the hen eggs, so as to make 

 the hatch come off more uniformly. 



In setting an incubator avoid overcrowding. It 

 is sometimes very tempting to put some eggs on the 

 top of a full tray, but in nine cases out of ten it 

 turns out very unsatisfactory. 



Before placing the eggs in the incubator have the 

 machine regulated and in good running order. After 

 the eggs have been thoroughly warmed a little 

 adjustment of the regulator may be necessary, but 

 not enough to cause much alarm. 



Many beginners make the mistake of not read- 

 ing the manufacturer's directions for operating the 



