BREEDING FOR EGG PRODUCTION 5 



been emphasized. Each year a surplus of pullet breeders has been placed in the 

 rnating pens in order that the offspring from such as proved unsatisfactory in 

 hatchability, in egg character, in broodiness, or in lack of persistency might 

 be discarded. 



After the discovery that five specific characteristics were associated with 

 high fecundit\-, the method of breeding was directed toward the establishment 

 of these in the entire flock. The characters bred for were early sexual maturity, 

 high intensit>, no winter pause, non-broodiness, and high persistency. The 

 early efforts were directed toward establishing early sexual maturity by the 

 selection of female breeders that began to lay at an early age, and this standard 

 has been rigidly adhered to. Efforts were next made to reduce broodiness through 

 the use of non-broody females or females with a low degree of broodiness for 

 breeding. High intensity was the third character sought for, and was established 

 in the flock by one hen, B785, hatched in 1917 and used first for breeding in 1918 

 and again in 1919 and 1920. Seven of the daughters of this hen and one son were 

 also used. Efforts to eliminate winter pause entirely followed the establishment 

 of high intensity. Breeding females were selected as far as possible that showed 

 no cessation of production between November 1 and March 1. The last character 

 to be established was high persistency. Selection of breeders for this purpose 

 was based on ability to lay late in the fall before undergoing annual molt. 



Throughout the experiment attention has been given to high hatchability, 

 and during the past five years special attention has been given to egg size and egg 

 character and to mortality rate as well as to the elimination of physical defects 

 and to the improvement of plumage color. 



All matings made since 1913 have been pedigree matings, and a complete 

 hatching record has been kept of all eggs set. Infertile eggs were removed on 

 the fifth day. All eggs carrying dead germs were removed on the fifth day or 

 on the eighteenth day, broken, and the embryos checked. Eggs were placed 

 in pedigree baskets on the eighteenth day and the chicks taken out on the twenty- 

 second day. All remaining unhatched eggs were then broken and the embryos 

 examined. Chicks were banded from the incubator using No. 3 pigeon bands 

 placed around the leg and transferred to the wing at two weeks of age to serve 

 as the permanent number of the bird. Sexes were separated at about eight 

 weeks of age, and pullets placed in the laying houses according to hatching date 

 at about 150 days of age. Complete pullet families were housed, except crippled 

 or diseased birds. 



The Changes in the Average Character of the Flock 



Progress in breeding for particular characters can best be measured by averages 

 from year to year, provided the number of birds concerned is sufficiently large to 

 be respresentative. In Table 1 are presented the averages for a considerable 

 number of characters throughout the experiment. The table includes only birds 

 bred for high fecundity in the flocks hatched from 1916 to 1932. Annual records 

 are not available on the flock hatched in 1919 because the birds were disposed 

 of after the hatching season on account of disease and parasites. 



The table shows that early sexual maturity was rather well established in the 

 1917 flock, and that the fluctuation in mean age at first egg has ranged from 185 

 to 212 days in a 16-year period. The fact should be stated that the mean age at 

 first egg of the 1913 flock was 255.61 days. 



