106 HATCHING AND REARING 



crease in direct proportion to the length of time they are 

 held before incubation. Eggs kept over three weeks are 

 rarely profitable. Incubator eggs should be kept in a cool 

 temperature previous to incubation; 50 degrees Fahrenheit 

 is about right. A high temperature in the room is apt to 

 start the development of the germ, but if the air is not 

 warm enough to keep the germ growing, the result is death. 

 If possible, hatching eggs should be placed with the large 

 end up, as this keeps the air cell in its normal position, and 

 prevents the necessity of frequent turning. When the eggs 

 are placed on the side, they should be turned carefully 

 every other day. A common method is to pack them securely 

 in boxes and turn the box every other day. 



Selecting the Hatching Eggs. If the pullets desired are 

 to lay eggs uniform in shape and color, these points must 

 be borne in mind when selecting the eggs from which they 

 are to be hatched. Especially is this true with regard to 

 color. If the breed used lays white eggs, all eggs with tinted 

 shells should be sold for food, and nothing but ivory-white 

 shelled eggs should be placed in the machine. If this rule 

 is followed for two or three generations, we can absolutely 

 eliminate tinted eggs from the strain. If brown shelled eggs 

 are produced, we should select those as nearly as possible 

 of uniform shade. Hatching eggs should also be selected 

 for uniformity of shape. Put no exceptionally long eggs in 

 the machine; they are often infertile, and frequently the 

 chick does not form properly, hence can not get out of the 

 shell. Neither should perfectly round eggs be hatched. A 

 uniform, normal shape is best. Malformed eggs should never 

 be set for hatching (Fig. 62) . They are usually infertile, but 

 even if they should contain a germ they will rarely hatch. 

 Size is important in selecting eggs for a hatch, and extremely 

 large or small ones should be rejected; if abnormally large, 

 they are usually double yolked, and rarely hatch out. Birds 

 which lay such eggs are usually extremely fat or out of health, 



