INCUBATION 



drying too fast after they come out of the shell, or 

 to be having difficulty to get out it is well to open 

 the machines and wet the eggs down thoroughly. 



Fertility The fertility varies with the season 

 that is, with the weather. At the beginning of the 

 laying season when the weather is cold the fertility 

 usually runs rather low. This is likewise true at 

 the end of the laying season when the heat of sum- 

 mer sets in. During the interval between these two 

 times of low fertility there will usually be one or 

 more periods during which the fertility will go down 

 and then come back again. This seems to occur even 

 though the weather remains about the same and 

 though there is no change in the method of feeding. 

 Fertility may be considered to be good when it runs 

 about 85%. When the fertility is running poor the 

 hatching of the eggs left in the machines after test- 

 ing will usually be poor also. 



Hatching. It takes longer as a rule from the time 

 that the ducklings pip the eggs until they hatch than 

 it does with chicks. To retain the moisture which is so 

 necessary during hatching, the machines are usually 

 shut tightly and are not opened until the hatching 

 is pretty well completed unless it becomes necessary 

 to add more moisture as indicated above. The little 

 ducklings should be left in the incubator until the 

 hatching is over and they are thoroughly dried off. 

 As soon as the hatching is completed, the ventilators 

 in the machines are opened to hasten the drying 

 process. If the ducklings open their bills and pant 



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