CHAPTER XXII 



INCUBATION 



Incubation is done by either natural or artificial means. 



In artificial incubation either a small or a large incubator 

 may be used. The small single compartment type is heated 

 by hot water or hot air, by gas, oil, or electricity. Either hot 

 air or hot water sj^stems may be used. The large incubators 

 are heated by electricity or hot water, by gas, oil, or coal. 



Incubators, with many compartments are called mammoth 

 incubators, which may be heated by gas, electricity, or coal. 

 The water system is used when coal or gas is used as a fuel. 



Incubation 



Natural | Hen 



Small 

 (Hot water < 

 or hot air) 



Artificial 



Mammoth 



(Hot water 



or electric i Electricity 



coil heat) Oil 



Diffusion 



Radiation 



Coal 



Gas 



\ Electricity 

 Oil 

 Gas 



Time Required for Hatching. — The number of days neces- 

 sary for hatching or incubation of eggs of the various kinds of 

 poultry are as follows: Fowl vary from nineteen days for 

 the light to twenty-one days for the heavy breeds. Geese 

 average thirty days, varying from twenty-seven to thirty- 

 three days. Turkeys, twenty-eight days, varying from twenty- 

 six to thirty days. Ducks average twenty-eight days, varying 

 from twenty-six to thirty-two days. Guineas average twenty- 

 eight days, varying from twenty-six to thirty days. Pigeons 

 average seventeen days, varying from sixteen to twenty days. 



Chick Production. — ^Strong, healthy chicks can be produced 

 only from the right kind of eggs. It will be observed that 

 eggs vary in size, shape, and color, as well as in inherited 



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