May 3, 1920.] 



Agricultural Gazette of N.SW. 



371 



An Infertile Egg. 



Temperatures of Eggs and Incubator. 



It may not be generally known that there is a difference between the 

 temperature of the eggs under incubation and that of the incubator in 

 which they are contained. The 

 temperature of the egg itself 

 in the early stages is generally 

 about 2 degrees Fah. below 

 that registered by the ther- 

 mometer in the incubator. 

 Thus if 102 degrees is shown 

 in the drawer at J inch above 

 the eggs, that of the egg itself 

 is about 100 degrees. After 

 the ninth day the temperature 

 of the eggs will rise to 101 

 degrees and the incubator to 

 103 degrees, at which it should 

 be allowed to remain. After 

 about the thirteenth day an- 

 other degree is gained by the 

 eggs, while the temperature in 

 the incubator still remains the same. About the nineteenth day 104 degrees, 

 should be allowed in the incubator, and that of the esgs will rise to 103 

 degrees. The temperature in the incubator should thereafter stand at 104 

 degrees to 105 degrees until the conclusion of the hatch. This is a critical 

 stage and the temperature of the incubator should be kept as steady as 

 possible and on the high side rather than lower. The effect of allowing the 

 temperature supplied by the incubator to fall down to, or below, that of the 

 eggs is to cause a reverse radiation from the eggs. It acts in this way : 



Instead of radiation from the 

 incubator supplying heat to 

 the eggs, there is an emanation 

 of animal heat from them. In 

 other words, the embryos are 

 giving off heat and are main- 

 taining the registration on the 

 thermometer at a false stand- 

 ard. The effect, of course, is 

 that instead of a progressive 

 development of the strength 

 of the embryos, they are being 

 weakened by the loss of their 

 own heat. Many cases of "dead 

 in the shell " result from this 

 condition. 



Testing Eggs for Fertility. 



Testing eggs for fertility, 

 while perhaps one of the most 

 simple operations that the novice poultry-keeper must learn, is yet of some 

 importance, and many cases come under notice where mistakes are made in 

 testing-out the infertile eggs, so much so that many, rather than run the risk 

 of throwing out valuable eggs, refrain from testing altogether, with the 



A Fertile Egg, showing embryonic development 

 at seven days. 



