DUCKS AND GEESE 



As the egg laying season advances the eggs laid by 

 the ducks tend to get a little larger. 



Temperature. Up to the time of testing, that is, 

 about the fifth day, the incubator is run at a temper- 

 ature of from 101 to 102 degrees. After the fifth 

 day the temperature is kept as near 103 as possible. 

 The most sensitive period for a duck egg is during 

 the first 3 or 4 days of incubation. If they are 

 allowed to get too warm during this time the germ 

 may be killed while if the temperature is too low, 

 development will be retarded. 



Position of the Thermometer. In figuring on the 

 proper temperature at which to run the incubator, 

 the thermometer should be so placed that the bulb 

 is on a level with the top of the eggs, preferably 

 touching a fertile egg. If the thermometer bulb 

 rests on an infertile egg, the temperature recorded 

 will be lower than the actual temperature of fertile 

 eggs in the later stages of incubation, due to the 

 animal heat of the developing embryos, with the 

 result that the machine would be operated at too 

 high a temperature. 



Testing. It is common practice to make only one 

 complete test. This is done on the evening of the 

 fifth day. Testing may be done by means of an or- 

 dinary candling dcAdce such as is used with hens' 

 eggs, each egg being examined separately. To save 

 time a piece of apparatus may be used which is sim- 

 ple in construction and which simplifies the process 

 of candling considerably. This may be termed a 



74 



