36 



FECUNDITY IN THE DOMESTIC FOWL 



breeding of 253 and 14 were quite different, though both these hens laid the 

 same number of eggs. Again, take birds nos. 386 and 911. One had a 

 winter record of 55 and the other of 52 eggs. Yet their daughters' average 

 winter productions were, respectively, 4.88 and 27.33 eggs. Many more 

 instances of this kind could be brought forward. Taken together, the 

 whole evidence shows beyond the shadow of a doubt that the presence of 

 high fecundity in an individual, and that factor which makes high fecundity 

 appear in the progeny, are two very different things, either of which may be 

 present in an individual without the other. We plainly have here the 

 basis for the distinction of phseno types and genotypes just as in beans. 



THE INHERITANCE OF EGG PRODUCTION IN PEDIGREE LINES 

 Let us now consider some of the evidence that such things as genotypes 

 of fecundity really exist in fowls. We may first examine some representa- 

 tive pedigrees covering four generations and showing the occurrence of 

 high and low fecundity lines. 



As a typical example of a high fecundity pedigree line in which the high 

 fecundity is genotypic, line D5D39 may be considered. In the presenta- 

 tion of this and other pedigree tables the following conventions are adopted. 

 The band numbers of the birds are in bold-faced type, and following the 

 band number of each female, her winter egg record is given in italic figures 

 enclosed in parenthesis. The band numbers of males are given in italics. 



PEDIGREE LINE 05039 



9 E232 (69) X d" 555 o 



Mean = 62 



9 F255 (48) X #564 



303 (64) X #563 

 136 (48) 



347 (69} X d" 562 , 



Mean = 61 



9 G 10 (100) 



14 (99) 



88 (23} 



524 (i 6) 



9 G 12 (16) 



19 ( 70) 



39 (100) 



53 ( 44) 



81 (34) 



85 (73) 



192 (57) 



213 (29) 



9 G 18 (61) 



27 (83) 



46 (116} 



196 (56) 



211 ( 36) 



248 (67) 



9 G 11 (47) 

 134 (///) 

 165 (35) 

 198 (39) 

 506 (16) 



Mean =57-74 



