60 



POULTRY FOR PROFIT 



2. Too little mois- 

 ture, which causes 

 excessive evapora- 

 tion. The chick lacks 

 bulk and is unable 

 to exert sufficient 

 pressure to break 

 the egg, or when it 

 does do this the in- 

 ner lining of the 

 shell dries on it and 

 keeps it from 

 moving. 



3. Irregular tem- 

 perature during in- 

 cubation, which 

 weakens the germ 

 so that the chick 

 dies before it can 

 free itself. 



4. Weakness in the chick, due to lack of vigor in 

 the parent stock. 



5. Too high temperature the first days of in- 

 cubation. 



6. Too low temperature in the under parts of 

 the egg. 



7. Strangulation, caused by the chick becoming 

 choked with unused albumen. 



8. Lack of adequate ventilation during third 

 week of incubation. 



9. Excessive ventilation during last half of in- 

 cubation period. 



10. Keeping hatching eggs too long, which 

 weakens the germ and causes loss of hatching 

 power. 



11. Failure to turn the eggs daily, which causes 



FIG. 19 



DIAGRAM SHOWING AIB CELLS AT 

 DIFFERENT STAGES OF INCUBATION 



