Incubation. — Part II 



1393 



Fig. 28. — Eggs for incubation: i, Selected; 

 2, non-selected 



HANDLING THE EGGS 



The eggs should not be placed in the incubator until it has 

 been run for several days and properly regulated, and all directions have 

 been followed in regard to setting up, 

 special attention having been given 

 to the manufacturers' directions con- 

 cerning ventilators, felts, trays, etc. 

 Eggs of a uniform size, shape, and color 

 should be chosen so far as possible, and 

 those with very porous or otherwise 

 defective shells should be eliminated. 

 (See Fig. 28.) A few more hours are 

 usually required in hatching eggs from the heavy type of fowls than are 

 needed for Leghorn eggs, so that it is not advisable to set the two kinds of 

 eggs together in an incubator. 



Turning the eggs. — From the time the eggs become thoroughly heated 

 until the chicks issue from the shells, more or less evaporation of the egg 

 contents takes place. Consequently, there is a tendency for the parts next 

 to the shell to become dried to the shell unless the egg is well turned at 

 frequent intervals. It is said that the sitting hen turns her eggs several 

 times during the day and night; but conditions existing in artificial incu- 

 bation do not admit of so many turnings. However, it has been found 

 essential to turn the eggs twice daily, beginning twenty-four to thirty-six 

 hours after they are put in the incubator and continuing up to the nine- 

 teenth day, on and after which the machine should be kept closed. The 

 additional fact that incubators, as a rule, do not supply the same amount of 

 heat to each egg makes it doubly necessary, not only that the eggs be well 

 turned twice each day, but that their positions on the trays be changed as 



regularly as they are turned . Regularity 

 in turning has much to do with the suc- 

 cess of the hatch . The best time to turn 

 the eggs is the first thing in the morn- 

 ing and the last thing at night. This 

 arrangement not only enables the oper- 

 ator to have a specified time for doing 

 the work, but it keeps the turnings as 

 far apart as is conveniently possible and 

 equalizes the space of time between 

 Fig. 29.-Turning eggs turnings — two important factors. 



Since the principal reasons for turning eggs are (i) to prevent drying 

 to the shell and (2) to equalize the heat, it is necessary that the eggs be 

 given a thorough shuffling. (See Fig. 29.) This may be done satisfac- 



