REVIEW 265 
6. Define line breeding; what are its possibilities in commercial breeding? 
7. Define ‘‘out-crossing’’ and give its use. 
8. What is meant by reciprocal crosses? 
9. What are the possibilities of sex control? 
10. Give a brief summary of the possibilities of different breeding systems. 
11. Define and give the fundamental advantage of selection. 
12. Give two results of proper selection. 
13. Enumerate and discuss briefly nine rules which should be considered in 
breeding for egg production. 
14. Give three features which should be considered in selecting for egg pro- 
duction. 
15. Discuss the factor of constitutional vigor in breeding. 
16. Enumerate some of the contributory causes to lack of vigor. 
17. What are some of the signs of vitality and lack of it? 
18. Give nine points which are associated with high egg production. 
19. What is the value of good size among egg, breeds? 
20. Discuss three factors which should be considered when breeding for meat 
production. 
21. Discuss “double matings” for color and plumage markings. 
22. What is meant by sexual dimorphism? 
23. Give some important considerations in breeding for color. 
24. What are the causes of ‘‘brassiness or creaminess?”’ 
25. Name some soil effects upon plumage and shank color. 
26. What, if any, is the effect of a previous impregnation upon subsequent 
chicks? : 
References.—Breeding Poultry for Egg Production, by Raymond Pearl, 
Maine Bulletin 192. Importance of Constitutional Vigor in the Breeding of 
Poultry, by Rice and Rogers, Cornell Reading Course Bulletin 45. Inherit- 
ance of Fecundity, by Pearl and Surface, Maine Bulletin 166. Appliances 
and Methods for Pedigree Poultry Breeding, by Pearl and Surface, Maine 
Bulletin 159. A Barometrical Study of Egg Production in the Domestic 
Fowl, by Pearl and Surface, U. S. Bureau of Animal Industry Bulletin 110 
(in two parts). The Single Testing System of Breeding for Egg Production, 
by D. F. Laurie, Department of Agriculture, South Australia. Breeding for 
Egg Production and Egg Types, by James Dryden, Utah Bulletin 92. 
