APPLICATION OF PRINCIPLES OF BREEDING 491 



Mating systems. Whenever Standard specimens of both sexes 

 can be produced regularly from a mating of a Standard male 

 and a Standard female, the practice is to mate in that way. This 

 is called the smgle-mating system. When the Standard require- 

 ments for males and females of a variety are such that the desired 

 type of male and female cannot be regularly produced from a mat- 

 ing of a Standard male and female, two distinct lines, or sub- 

 varieties, are developed, one to produce Standard males and one 

 to produce Standard females. This is called the double-mating 

 system. Whether or not the necessity for double matings shows 

 inconsistency in the Standard depends upon the points of view. 

 From the practical poultryman's point of view it does ; from the 

 fancier's point of view it does not. The occasion for double mat- 

 , ings arises principally because of sexual differences in plumage 

 color, which the fancier in some cases would intensify and in others 

 would remove. In either case he can produce what he considers 

 the finest type in one sex only at the sacrifice of his favorite color 

 in the other. The particular reasons for special mating will appear 

 in the discussions of matings of such varieties as the Barred Plym- 

 outh Rock and the Brown Leghorn. Here it need only be said, 

 with reference to the general question of the system to be used, 

 that in all varieties for which the double-mating system is com- 

 monly used, a breeder who adopts the single-mating system cannot 

 compete, in the production of high-quality stock, with those who 

 use the other system. Intermediate matings (so called) are some- 

 times used, in which a male about medium between the two types 

 of males used in the distinct lines is mated with females of both 

 types. That method may give satisfaction when a breeder works 

 only for his own pleasure, or when competition is not too strong. 



Details of Matings 



In general a character common to a number of breeds or varieties behaves 

 the same way wherever found. Its behavior sometimes varies because of differ- 

 ent ancestral influences, but on the whole the rules for mating which apply 

 to a character or a combination of characters in one variety will apply to all 

 similar characters and combinations. Hence, in a general consideration of de- 

 tails of mating poultry the subject may be greatly simplified by considering 

 similar types in groups. The special details of mating are principally color 

 details. In consideration of shape points the application of the rule requires 



