41 



Males' Phenohjpical Character. 



HH males on HH hens !2:ive all high hatchability. 

 HH males on Hh hens give all medium hatchability. 

 HH males on hh hens give all medium hatchability. 

 Hh males on HH hens give all high hatchability. 

 Hh males on Hh hens give all medium hatchability. 

 Hh males on hh hens give all low hatchability. 

 hh males on HH hens give all medium hatchability. 

 hh males on Hh hens give all low hatchability. 

 hh males on hh hens give all low hatchability. 



Males' Genotypical Character. 

 HH males on HH hens give all HH daughters. 

 HH males on Hh hens give 50% HH and 50% Hh daughters. 

 HH males on hh hens give all Hh daughters. 

 Hh males on HH hens give 50% HH and 50% Hh daughters. 

 Hh males on Hh hens give 25% HH, 50% Hh, and 25% hh daughters. 

 Hh males on hh hens give 50% Hh and 50% hh daughters, 

 hh males on HH hens give all Hh daughters, 

 hh males on Hh hens give 50% Hh and 50% hh daughters, 

 hh males on hh hens give all hh daughters. 



Both parents must carry the H factor in order to be phenotypically good hatchers. 

 Hens cannot rank in the first class unless they carry the gene H in homozygous 

 condition and are mated to H-bearing males. These observations indicate a 

 cumulative value for the factor H and show why the male by failure to contribute 

 at least one-half H-bearing sperm ranks a genotypically high hen as a medium 

 hatcher. Furthermore, lioth HH and Hh males probably give about the same 

 hatching record from HH hens. The progenj^ test alone can give a clue to the 

 genetic composition of males if pullets of unknown formula? are used as breeders. 



Selection for high and low hatchal)ility did not give results in two generations 

 according to Dunn ('23). The probaI)le explanation is that he used in his low line 

 genotypically high (HH) hens that gave medium hatching records because they 

 were mated to hh males. If such were the case, no appreciable separation could 

 take place in but two generations. There may also have been a lack of HH or Hh 

 males in his high line. Selection for high hatchability with the female as a guide 

 and using cockerels from hens that hatched well has been a slow but progressive 

 process in our flock, as already shown in table 17. In table 9, the mean hatcha- 

 bility of the dams of the males used for breeders is about 70 per cent. This would 

 indicate that, on the average, the breeding males came from Hh hens. Thus, only 

 in the later years of the period could any considerable percentage of males have 

 been of the formula Hh. A study of earlier records shows that practically all the 

 males must have been of hh composition, because they came from medium or low- 

 hatching dams. 



SUMMARY. 



1. No correlation was found between fertility and hatchability in 758 pullets. 



2. Fertility in the hen behaves as an individual characteristic with a fair degree 

 of constancy from year to year. 



3. Fertility does not appear to be transmitted from mother to daughter. 



4. Hatching power is more constant from j'ear to j'^ear in the same hen than is 

 fertility. 



5. Hatching power gives evidence of being transmitted from mother to daughter. 



6. Fertility in the male behaves as an individual characteristic and probably 

 with some constancy in the same individual from year to year. 



7. The fertility record of a hen is no index to the fertilizing abihty of her sons. 



8. Fertility does not appear to be transmitted from sire to daughter. 



9. Hatchability is more constant from year to j'ear in the same male than is 

 fertility. 



10. Fertility does not appear to be transmitted from sire to son. 



11. The hatching power of a male cannot be judged by his dam's hatching 

 record. 



