INCUBA TION 89 



mixed colors should be discarded, as well as eggs 

 that are abnormally large or small. 



Care of Eggs for Hatching. The best hatch is ob- 

 tained from eggs placed in the incubator the same day 

 on which they are laid. Eggs keep in prime condition 

 for hatching up to the tenth day; if 2 wk. old they are 

 safe for incubation; but if older than this they seldom 

 hatch well, although some eggs that have been kept a 

 month will hatch. Eggs keep best in a uniform tem- 

 perature of about 55 F. in an atmosphere free from oil 

 and other bad odors. The vitality of eggs that are 

 exposed for any length of time to a temperature below 

 40 F. is impaired. 



Eggs for hatching are shifted at least every other 

 day so that the yolks will not settle to one side, stick 

 to the shell, and thus destroy the germ. Preferably, the 

 eggs should be stored small end down, either in a 

 regular packing crate or any suitable receptacle. 



Eggs for hatching are injured if they are washed; 

 washing removes the natural glaze from the shell, and 

 such eggs do not hatch well. Though not advisable to 

 hatch dirty eggs, such eggs hatch better in soiled con- 

 dition than they would if washed. 



INCUBATORS 



An incubator is an apparatus by means of which eggs 

 may be artifically kept at the proper temperature for 

 hatching. Many different styles and sizes of incu- 

 bators are now in use, some of them being adapted for 

 all sizes of eggs from those of the bantam to those 

 of an ostrich. Incubators range in size from those 

 the capacity of which is limited to a few dozen eggs to 

 those that are capable of incubating many thousand 

 eggs. The machines most commonly used have capaci- 

 ties that range from 5 to 30 doz. hen's eggs or a smaller 

 number of any eggs that are larger than hen's eggs. 



Though many different types of incubators are made, 

 with but few exceptions in outward appearance they 

 resemble the one shown in Fig. 1. 



