CHAPTER XI 

 ARTIFICIAL HATCHING 



By artificial hatching is meant doing without the sitting 

 hen, and supplying artificially the heat necessary for hatch- 

 ing the eggs. Heat generated by burning kerosene, coal, or 

 gas is commonly used for this purpose. In natural iticuba- 

 tion the management is simple, for the mother hen takes 

 charge of all the details, but in the artificial process the 

 poultryman is responsible for every step. Artificial incuba- 

 tion dates back to prehistoric times. We have ancient 

 records which prove that the Egyptians and Chinese hatched 

 eggs in specially constructed ovens, which in some cases 

 were heated by fermenting manure, ia others by fire. No 

 thermometers were used to determine the temperature, but 

 operators, through years and generations of practice, became 

 so expert that they could tell the proper heat just by remaining 

 in the room. The past twenty-five years have seen a re- 

 markable stride ia the development of commercial incubators, 

 which to-day are used more or less extensively on all poultry 

 farms. 



The Incubator. — The incubator is a machine designed 

 essentially for the hatching of eggs. There are two types 

 of incubator, one known as the hot air and the other as 

 the hot water machine, the hot air being commoner (Fig. 68). 

 In these the heat is conveyed to the eggs by a current of 

 warm air which forms around the lamp chamber, and when 

 hot enough is passed down over the eggs from above. The 

 air in the incubator compartment of the hot air machine is 

 heated by a tank or by pipes which pass above the eggs. 

 There are two general types of incubators, the individual 

 and the mammoth machine. Individual incubators range 

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