EGG PRODUCTION AND SELECTION 



DR. H. D. GOODALE 



MASSACHUSKTTS AliRIfUl.TURAIi E.Xl'KRIilKXT STATION, 



Amherst, Mass. 



About three years ago breeding for increased egg pro- 

 duction was begun at this station with Rhode Island Reds. 

 A report on some of the chief features of the work will be 

 published in the near future, but because of the recent dis- 

 cussion in this journal, by Pearl and Castle, of egg pro- 

 duction in relation to selection certain features of egg 

 production in this breed are of particular interest at this 

 time. 



The winter record of a hen depends upon two main in- 

 ternal factors aside from possible environmental factors. 

 First, the date at which the first egg of a pullet is pro- 

 duced, which may be taken as an index of the attainment 

 of sexual maturity; and second, the rate of production 

 after the onset of egg-laying. The former in turn depends 

 upon the time when she was hatched and upon her rate of 

 growth. The latter factor, i. e., rate, is controlled in part 

 at least by an internal mechanism. In the Reds it is clear 

 that of the two factors the preponderant effect is exer- 

 cised by the factor of maturity. The observed differences 

 in rate of production are of less, though by no means neg- 

 ligible importance. In the Barred Rocks, as far as I have 

 been able to learn, conditions are reversed, in that the 

 rate of production appears to exercise a greater mlluciicc 

 on the kind of record a hen makes than the age at which 

 she produces her first egg, although the latter is also a 

 factor. Identical records as expressed m number o i .-i^ 

 per unit of time may therefore result, but it is clear that they 

 are not directly comparable. The use of the age at first 

 egg as a criterion of sexual maturity involves some diffi- 

 culties, but it is the best objective criterion readily avail- 

 able and corresponds at least roughly with the general 

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