106 INCUBATION 



hands or with hands that have any substance on them 

 which might adhere to the shells. 



Test the eggs on the sixth and the seventeenth days, 

 but do not turn or cool them while testing them. Cool- 

 ing and ventilating should be done according to the 

 instructions given in the book of directions that accom- 

 panies each machine. Cooling helps to soften eggs. 



Be sure that the thermometer is accurate. If your 

 machine is supplied with a suspended thermometer, see 

 that the bulb is just 2 in. above the wire of the egg 

 tray. Do not allow the thermometer to go above 103 F., 

 except when the chicks are coming out lively, at which 

 time it may go as high as 105 F. without injury. 



Do not open the door of the incubator after the eggs 

 begin to pip. Close the ventilator when the chicks begin 

 to come out and keep it closed until the hatch is com- 

 pleted, unless the hatch is very large and the chicks 

 are crowded, in which case the ventilators may be 

 opened when the hatch is two-thirds off. Open the venti- 

 lator and wedge the door slightly ajar after the hatch 

 is over and the trays containing the shells have been 

 removed. Allow the chicks to remain in the incubator 

 for from 24 to 36 hr. Do not feed or water the chicks 

 while they are in the incubator. 



FACTORS THAT INFLUENCE SUCCESS IN 

 INCUBATION 



The factor of prime importance in incubation is the 

 vitality of the eggs, and this depends on the vitality of 

 the fowls that produce them. 



Eggs for hatching should all be of one kind, size, and* 

 color. 



Only smooth and well-formed eggs should be used for 

 hatching. Eggs of bad form or with rough shells should 

 be discarded. 



The best eggs for hatching are those that are placed 

 in an incubator on the day they are laid; eggs are in 

 good condition for hatching up to 10 da. after they are 

 laid; after they are 2 wk, old they are unreliable. 



