IMPROVING ^CC PRODUCTION BY BREEDING. 235 



The first question which will occur to the breeder's mind is 

 as to whether there are any external characters by which the 

 nine different types of males can be distinguished one from 

 another. Unfortunately no such external criteria have yet been 

 discovered. If it could be done it certainly would be of a great 

 aid in breeding for egg production. The only way that we know 

 now, however, by which it is possible to form a judgment as to 

 a male bird's innate, inherited qualities in respect of egg pro- 

 ' duction is through his progeny. We must find out what his 

 daughters do. Then the proportion of mediocre layers and poor 

 layers amongst his progeny furnish at once a clue as to his 

 probable composition. The diagrams show how one may form 

 this judgment. 



One interesting point brought out by the diagrams is that, 

 with the exception of a Type i male (Fig. 74, A), the mating 

 of any sort of male with high producing hens only, results in a 

 f^ock of male offspring of better average quality, taken as a 

 whole, than the sire himself. In other words, the use of high 

 producers, proven by the trap-nest, as the only females for 

 breeding purposes, "grades up" very rapidly the cockerels pro- 

 duced. 



The whole system of breeding here outlined is an application, 

 in the simplest form possible of two principles, one general and 

 the other special to the present case. 



The first is the general principle of the progeny test in breed- 

 ing for performance. This is the principle which has led the 

 plant breeder to such notable triumphs during the last fifteen 

 years. In my judgment no system of breeding for performance 

 in animals not fundamentally based upon it will ever achieve 

 any permanent success. The second principle, is the recogni- 

 tion of the significance of the male in breeding for egg produc- 

 tion. It has been the custom in trap-nesting work to reckon 

 pedigrees in the female line only. This we can now see to be 

 an essentially futile procedure, so far as concerns the daughters. 

 To say that "this pullet is the daughter of Lady Splendissima 

 (with a tremendous record)" is perhaps good advertising. It, 

 however, conveys no information of any special value to the 

 breeder, until he knows who was the Lady's consort in this 

 particular reproductive venture 



