THE INCUBATION OF HENS' EGGS 197 



has been strong and vigorous for years and without serious 

 outbreak of disease of any kind. It should be recognized as 

 simply a precautionary measure to eliminate any disease 

 germs that may be on the outside of the egg, and not in any 

 measure a sure preventive of chick diseases. 



Incubation Periods. — The number of days necessary for 

 the incubation of the eggs of the various species of poultry 

 are as follows: chickens, varying from 19 for light breeds to 

 21 for heavy Ijreeds; turkey 28, varying from 20 to 30; all 

 ducks except the Muscovy 28, varying from 2() to 32; Mus- 

 covy ducks 33 to 35; goose 30, varying from 27 to 33; guinea, 

 varying from 26 to 30, and pigeon 17 from tlie day tlie second 

 egg is laid, but varying at times from 1(> to 20 days. 



Relative Hatching Efficiency of Hens and Incubators. — The 

 time has passed when the cjuestion of the desirability of 

 having an incubator on a farm where upward of one hundred 

 and fifty chickens are raised annually is any more debatable 

 than the desirability of having a cream separator, seed 

 tester, or any similar piece of modern farm equipment. 

 Hens are uncertain hatchers. Broodiness depends very much 

 upon the season and the condition of the hens. A late spring 

 means late laying, late setting,' and hatching. The time of 

 hatching determines C(uite largely whether jjuUets are in 

 laying condition by the following winter. And further, it 

 is usually difficult to secure enough broody hens at one time 

 to handle a very large number of eggs. 



Concerning the efficiency of incubators as hatchers, 

 Pearl^ makes the following statement, which would be 

 concurred in spirit by the majority of i)ractical poultrymen 

 and investigators. 



"In the experience of this station, with proper manage- 

 ment during and subsequent to incubation, the chicks so 

 produced are fully the equal in constitutional vigor, average 

 duration of life, and productivity, of hen-hatched chicks. 



' The author takes the position with reference to the use of the terma 

 "sit" and "set," or their derivatives, as describing the act of a broody hen 

 in incubating eggs, that good use, rather than any rule of technical gram- 

 marians, should be the test applied. The terms "set," "setters," and 

 "setting" are used throughout this work. 



- Poultry Management at Maine Station, 1913. 



