4 Poultry Bulletin 



May that fertility always runs highest. At other seasons of the year fer- 

 tility runs materially lower depending largely upon conditions under 

 which the birds are kept and the extent to which they have been forced 

 for egg production. It is a known fact among hatcherymen of the coun- 

 try that the beginning of the hatching season, along in February, fertility 

 will run fair, then most every year there comes a time along in the early 

 part of March when there comes a slump in fertility and hatches fall off 

 proportionately. This slump is followed in the course of a few weeks by 

 a rapid rise in fertility to the point of normal spring conditions. To elim- 

 inate this late winter slump has been the object of hatcherymen for many 

 years. 



The factor of breed of birds materially influences fertility in that the 

 lighter, active, Mediterranean breeds always produce a much higher fer- 

 tility than the heavier, less active, American breeds. The poorest fer- 

 tility of all comes from the heavy, slow-moving, inactive, Asiatic breeds. 



The age of birds influences normal fertility materially in that the fer- 

 tility from mature pullets usually runs higher than that from yearling or 

 older hens, especially is this true if the pullets have not been forced for 

 an exceptional egg production previous to the hatching season. The 

 reason for the general slump in fertility from yearling or aged hens is the 

 fact that they are not usually allowed to recover fully from the effects of 

 previous periods of heavy laying. 



The amount of egg production materially influences fertility in the 

 following manner. Birds which have been heavily forced for egg pro- 

 duction, especially for some time previous to the period of saving eggs 

 for hatching have apparently laid out of their system and out of their 

 body some unknown yet very essential factor which is essential in the 

 production of fertile eggs. Birds just coming into production seem to be 

 able to produce a far higher fertility, probably as a result of an extended 

 rest period which has allowed them time to accumulate in their system 

 an abundant supply of this unknown factor which is apparently so essen- 

 tial for high fertility and strong germs. A general statement covering 

 this condition can well be expressed as follows: — breeding birds just 

 coming into production, well fleshed with an abundance of yellow pig- 

 ment produce a very large percentage of fertile eggs with strong germs, 

 while hens which have been laying heavily for a long time, which are not 

 supplied with large quantities of fat, and from which the pigment has 

 been largely bleached produce eggs of inferior hatching qualities due to 

 low fertility and weak germs. 



From the above discussion it can be readily seen that fertility is de- 

 pendent in large part upon managerial conditions. The forcing of breed- 

 ers for heavy egg production for a long time previous to the hatching 

 season, by the use of heavy protein mashes, artificial illumination and 

 other known stimulating methods is surely a detriment to fertility. 



