INTERNAL FACTORS INFLUENCING EGG PRO- 

 DUCTION IN THE RHODE ISLAND RED 

 BREED OF DOMESTIC FOWL. Ill 



DR. H. D. GOOD ALE 

 Massachusetts Agricultural Experiment Station, Amherst, Mass. 



Winter Egg Production and the Genetic Constitution 

 of Rhode Island Reds.— Pearl, 12, found his Barred 

 Plymouth Rocks fell into three well-defined classes in re- 

 gard to winter egg production, viz., those that did not lay 

 at all before March 1, the zero class ; those that laid less 

 than thirty eggs with a mean at about 16 eggs, the medi- 

 ocre producers; and finally those that laid over thirty 

 eggs, the high producers. Pearl has stated, however, 

 that the existence of the two classes of birds, mediocre 

 and high, is the important point rather than the number 

 of eggs at which the dividing line falls, which may be 

 below 30 eggs in some flocks and above 30 in others. 

 Since the record of No. 5080 is that of a typical true medi- 

 ocre producer; it is clear why the division point need not 

 fall at a particular number of eggs. If, however, the 

 numerical record of a pullet is made the only basis for a 

 division point, it may be pointed out that the point could 

 be shifted by differences in environment. If, on the 

 other hand, under the same general environment one 

 flock was found to have a different point of division from 

 the second flock, the latter could not be considered genet- 

 ically like the first. Thus far, no satisfactory division 

 point has been found for our Rhode Island Reds, due 

 probably to the few records of the type shown by No. 

 5080 (that is, to an absence of true mediocre producers) 

 and to the great variability in age at first egg, associated 

 with a comparatively uniform rate of production after 

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