132 HATCHING AND REARING 



EXERCISE No. 23. Have one or more members of the 

 class construct a homemade egg tester, as described in the 

 text. When the eggs are being hatched for the above exer- 

 cises, they can be tested frequently, to study the appear- 

 ance of fertile and infertile ones and to watch the develop- 

 ment of the embryo as seen through the shell. 



EXERCISE No. 24. Weigh fifty eggs before placing them 

 in the incubator. Weigh them each day until the chicks 

 hatch. Weigh the chicks after hatching. How do you 

 account for the regular loss of weight? How much is the 

 loss per 100 eggs for the entire twenty-one days? 



THOUGHT QUESTIONS 



1. What is meant by the term " artificial hatching" ? 



2. What kinds of fuel are sometimes used to generate the heat? 



3. Describe the ancient Egyptian ovens. 



4. What is an incubator? 



5. What two types of incubators are in general use? 



6. Describe the difference between the individual and mammoth 



incubator. 



7. Describe the general type of individual incubator. 



8. Describe the mammoth incubator as to its usefulness. 



9. What are some of the important points which an incubator should 



possess? 



10. Describe a suitable location for an incubator. 



11. What is the proper heat to incubate an egg? 



12. How is the proper heat maintained and controlled? 



13. What is the proper degree of moisture for incubation? 



14. Why is fresh air necessary for incubation? 



15. How would you prepare an incubator to receive the eggs? 



16. What are the essential points in the care of the lamp? 



17. How is the proper moisture content maintained? 



18. What precautions should be taken when putting the eggs in the 



machine? 



19. Give a rule for turning the eggs in the machine. 



20. Why should the hatching eggs be turned during the period of 



incubation? 



21. Give a rule for cooling the hatching eggs. 



22. What is the best practice to follow in testing the eggs? 



23. What hatching records should be kept? 



24. What special attention should the incubator receive during the time 



the eggs are hatching? 



25. Enumerate some things which should be avoided in artificial 



hatching. 



Reference. United States Farmers' Bulletin 236, Incubation and 

 Incubators. 



