346 ARTIFICIAL INCUBATION 



the sand tray or other device for moisture should be removed, and 

 the nursery tray placed in proper position. The wire in front of 

 the egg trays should be opened, and the tray placed with this 

 opening in front, so that, when the chicks are attracted to the 

 front by the light, they will fall down into the nursery. In most 

 machines it is well to cover the glass with a cloth or burlap during 

 the hatching. This keeps the chicks more contented and prevents 

 crowding, and when the burlap or cloth is removed they are 

 stronger and better able to protect themselves. 



If the hatch has been properly conducted, it should start about 

 the nineteenth or twentieth day after the eggs were placed in the 

 machine, and all chicks which are to hatch will probably be out 

 at the beginning of the twenty-first or twenty-second day. This, 

 however, will vary somewhat with the temperature at which the 

 machine has been operated and with the character or type of eggs 

 set. The higher the temperature the earlier the hatch will start; 

 large b^o^^^l-shellcd eggs from the heavy breeds require from one- 

 half day to a day longer than the thinner-shelled eggs from the 

 lighter breeds. The one important thing at this time is that the 

 hatch should be uniform and complete soon after the first pipping. 



A prolonged hatch is rarely a successful one. If a hatch does 

 not turn out properly, it is well for the operator to look over the 

 records and see if he is at fault. The chicks should be left in the 

 machine from twenty-four to thirty -six hours after all are hatched. 

 As soon as the hatch is complete, the egg tray should be removed, 

 and a little fine grit and oatmeal be thrown into the nurserj^; this 

 will stimulate the digestive system of the chicks and teach them 

 to pick up feed. It is rarely of any use to remove from the shell 

 chicks which are incapable of getting out themselves. 



Poor hatches may be due to various causes, such as poor eggs, 

 faulty condition of the breeding stock, or want of care previous 

 to putting in incubator. Given good eggs at the start, disappoint- 

 ment is most often the result of inexperience and poor management 

 of the machine, especially shown by irregularity in attendance 

 and imperfect regulation of the ventilation and humidity. To 

 operate an incubator successfully'- the attendant must make up his 

 mind to put considerable thought and effort into the work and to 

 perform the duties methodically. 



Another factor in low hatching is a poor thermometer. To 

 prevent this, the accuracy of the thermometers should be tested 

 at the beginning of each season by comparing them with a clinical 



