50 MASS. EXPERIMENT STATION BULLETIN 215. 



The Sire's Potential Production as a Guide in Selecting Males. 



The average annual egg production of the daughters of a sire we have called 

 his potential production. In other words, in order to know the potential breeding 

 ability of a sire, there must be a trap-nest record of his daughters. This fact greatly 

 reduces the usefulness of the method with many poultrymen. Records at this 

 Station indicate very clearly, however, that males vary widely in their ability to 

 sire daughters that make high annual records. If it were possible to recognize 

 such sires in advance, their usefulness in the flock could be made many fold greater. 

 Referring back to Table 2: the column giving the sires' potential production is 

 very similar to the average egg yield of the daughters for the respective years. 

 It differs only in those cases where some of the sires were used for more than one 

 breeding year. A comparison of this column with the one headed Sires' Inherited 

 Production shows that in the early years the inherited production w^as higher 

 than the potential production, but beginning in 1917 the reverse is the case; clearly 

 indicating that the flock had been developed by the method of breeding to a higher 

 degree of prepotency. This greater prepotency in the last four or five years is due 

 to the fact that the flock has increased in the percentage of early maturing birds, 

 in the percentage of birds that do not show the winter pause, in the percentage 

 that are free from broodiness, and in the annual rate of production. As evidence 

 of this fact, there are now families (all the daughters of a hen) that are non-broody. 

 Other families show no winter pause, others show a uniformly higher rate, etc. 

 There is still a wide range in the annual egg production of the females in the flock. 

 This range may be explained on the Mendelian basis as we have shown elsewhere. 

 The statement still holds good that there is no guide in selecting the sire that is 

 as certain and reliable as the progeny test or the potential production. 



How TO Select Cockerels. 



A great many poultrj'men use cockerels to a considerable extent in their breeding 

 operations; and even where cockerels are used only to a minor degree for breeding 

 purposes the first year, it is necessary to select and reserve considerable numbers 

 for future sires. Any guide in the selection of cockerels, then, has a double value 

 to poultrymen. 



We have previously shown that the average annual records of the hens in the 

 dam's pedigree is of about the same value as the average annual record of the 

 hens in the sire's pedigree, so far as determining what the daughters from such 

 matings will produce is concerned. Selection of cockerels on their mothers' annual 

 records alone is a very inefficient and inaccurate method, compared with the five- 

 generation pedigree method we have used here. In our opinion, therefore, there is 

 no other method of choosing the cockerels to be used in breeding for egg production 

 that is as satisfactory as the combined sires' inherited production and dams' in- 

 herited production behind such cockerels. 



How TO Select Cocks. 



Too much stress cannot be laid upon the importance of making full use of breed- 

 ing males that have a demonstrated ability to sire heavy egg laj'ers. The history 

 of a good many flocks shows that the great producing hens from the flock trace 

 directly to a very few outstanding males. The same principle holds here as in 

 breeding the higher domestic animals. Sires of proven ability are invaluable. 



The cock may be selected both on the pedigree basis and on the progeny test. 

 The yearling cock will have daughters that have a winter record rather well along 

 by his second mating season, if he has been used as a cockerel. Winter records 

 are known to be of great value as guides to annual records. Therefore, the yearling, 

 cock can be selected with a good deal of certainty as to what contribution he will 

 make to the flock. As a two-year-old, he will be a strictly tested individual; and 

 if possessing the proper amount of vigor, and if properly handled, can be used 



