BULLETIN No. 159. 



APPLIANCES AND METHODS FOR PEDIGREE 



POULTRY BREEDING.* 



By Raymond Pearl, and Frank M. Surface. 



The primary and most fundamental requirement in all breed- 

 ing work, whether conducted for scientific or utilitarian pur- 

 poses, is that at any stage of the work there shall be an exact 

 knowledge of the ancestry (to as remote a degree as possible) 

 of each of the individuals composing the breeding stock. A 

 successful outcome of such work depends upon, among other 

 things, an adequate system of keeping pedigree records. Not 

 only must the pedigree records be accurate and systematic on 

 paper, but they must also be trustworthy. To insure that they 

 shall be trustworthy it is necessary that the concrete breeding 

 operations be carried on in such systematic fashion that errors 

 in. or contamination of the pedigrees either will not occur, or if 

 they do occur will be at once detected. That is to say, breeding 

 operations must be so systematized that, for example, there can- 

 not arise in the breeder's mind any doubt that the actual parents 

 of a given individual are the animals which he supposes to be 

 the parents. 



Now so long as breeding operations are conducted on a 

 restricted scale involving few individuals and pedigrees, the 

 matter of keeping pedigrees is a tolerably simple one. But 

 when the breeding stock rises to considerable numbers, as it 

 very quickly does with small animals like poultry, the pedigree 

 records and the whole machinery of breeding tend to become 

 very intricate and complicated. With this increase in complex- 

 ity inevitably comes an increased tendency towards error in the 

 records. To gain and maintain simplicity and accuracy in the 

 pedigree breeding of poultry involves the practical solution of 

 a whole series of rather complicated problems of technique. In 

 the breeding work at this Station working solutions of some 

 of these technical problems have been reached. In every 



* Papers from the Biological Laboratory of the Maine Experiment Station, No. 6. 



