2QO PRINCIPLES OF FARM PRACTICE 



to the growing embryo. The following rule should be ob- 

 served (Lewis) : "Begin turning on the evening of the third 

 day, continue this process morning and evening, until the 

 evening of the eighteenth or nineteenth day, or until the 

 eggs show signs of pipping. Then prepare the machine for 

 hatching, and do not remove the tray for any purpose." 



Good ventilation is essential. A current of air should 

 constantly move slowly through the incubator. As the method 

 of ventilation depends upon the type of incubator it is usually 

 a safe practice to follow the directions furnished with the 

 machine. 



Evaporation may be controlled by increasing the moisture 

 in the incubating room and within the chamber. This may be 

 done in several ways such as by frequent sprinkling of the 

 walls and floors of the room, by using moisture pans under 

 the egg trays, and by frequently sprinkling the eggs with 

 warm water. 



The eggs should be tested by means of a candler on the 

 seventh day for infertile eggs, dead germs, germs adhering 

 to the shell, and cracked eggs, and on the fourteenth day for 

 dead germs. 



From the time the eggs begin to pip the incubator should 

 be undisturbed. At this time the nursery tray should be in 

 place to receive the newly hatched chicks. After hatching 

 the chicks may remain from twenty-four to thirty-six hours 

 in the nursery tray, and then be removed to the brooder. 



Care of chicks after hatching. If the chicks are hatched 

 in an incubator, a brooder must be employed to take the place 

 of the hen. Essentially it is a box in which heat may be main- 

 tained and regulated in much the same way as in an incubator. 



The brooder should be clean and the floor covered with 

 fine sand over which short cut clover or grass has been scat- 



