36 POULTRY LABORATORY GUIDE 



will appear in size approximately as fol- 

 lows : — 



5tli day, J of one inch deep. 

 10th day, g of one inch deep. 

 15th day, | of one inch deep. 

 19th day, | of one inch deep. 



If the air cell is too large, moisture must be in- 

 creased to stop rapid evaporation, and if too 

 small, evaporation must be increased. An air 

 cell which is not in its normal position at the 

 large end of the egg will probably result in a 

 crippled chick if it succeeds in getting out of the 

 shell. It is caused by insufficient turning. 



II. Any egg which appears clear or translu- 

 cent with no dark fines appearing in its centre 

 is infertile. Mark all infertile eggs in some dis- 

 tinguishing manner, and put in separate tray. 

 They may be used for chick feeding when hard 

 boiled, and if tested on the fifth day are perfectly 

 safe for culinary purposes. 



III. A normal egg will show an air ceU with the 

 edge clear-cut and distinct; upon slightly re- 

 volving, the germ will be seen to move about in 

 the egg. Rotating from the germ and circulating 

 around in the egg will be seen numerous dark 

 lines or veins. 



An egg showing a fixed bright red line in the 



