Fertility of Eggs 151 



ment station publication:* " Where the incubator 

 is placed in a room whose temperature is reason- 

 ably even and is properly managed, a high percentage 

 of hatch may be expected only (a) when the hens 

 have plenty of exercise, (6) when the eggs are 

 freshly laid." 



After the male is removed, the eggs are thought 

 to be fertile for a few days, "from four to four- 

 teen days" is given by some authors. The following 

 gives the results of definite observations :f "On the 

 farm of the Ohio State University, 40 Leghorn hens 

 which had previously been kept without males 

 were placed in pens with the male birds February 

 18, and the percentage of fertile eggs observed for 

 nine days after mating. This increased regularly 

 from 0, on the day of mating, to 95 per cent on the 

 eighth day after mating. July 1 the males were 

 removed from the pens. The fertility of the eggs 

 was apparently not materially affected until the 

 twelfth day after removing the roosters. . . . 

 Unfortunately the eggs were saved only fifteen days, 

 and hence it is not shown how long hens must be 

 removed from the male before all the eggs become 

 infertile." 



For the greatest production of eggs, males are 

 not required except for the breeding-pen. Many 

 poultrymen who have made a speciality of egg 



*Bulletin No. 158, Michigan Agricultural Experiment Station. 

 fAgricultural Student I (1894), in Experiment Station Record. 



