Breeding Better Poultry

by THEODORE C. BYERLY

THE AVERAGE hen on our fathers' farms laid 86 eggs a year. Today the average is 118 eggs, and in some flocks it is about twice that. Changes in management, systematic trap-nesting, and selective breeding brought about the improvement. The amazing wartime yield of eggs and meat, far exceeding all peacetime records, shows what a well-organized industry, aided by research, can accomplish.

But we are not satisfied : Experimental flocks and progressive breeders of poultry demonstrate how we can get even more eggs and more profits. For, as egg production increases, the income over feed costs rises more rapidly, and higher production is had at a lower cost per dozen eggs. In the better flocks, also, more eggs are laid in the winter months, when prices normally go up. Hard economics like this underlie the experiments directed toward improved blood lines.

Many poultry breeders have developed strains of chickens of the more popular kinds that lay 200 to 250 eggs during the first laying year—provided, of course, feeding, management, health, and sanitation are of the best. A breeder develops these outstanding strains by mating selected birds—selected because of proved ability to lay, pedigree, handsome appearance, and, finally, family proof that they can pass on to their offspring the genetic factors necessary for high egg production.

We have found by analyzing many records that selection and mating in this way enable many poultrymen to maintain high production and that the method is effective also in flocks that are not so good. In other words, rigorous selective breeding will improve a flock in a few years to a peak that can be maintained, but not heightened, by further selection. But if selection stops, production drops. Improvement through selective breeding is directly proportional to the correlation between individual and family performance on the one hand and genetic make-up on the other. To find out whether by developing and crossing inbred families we could boost average egg production beyond the level reached by such family selection and line-breeding, we have made comparisons of the two methods at Beltsville each year since 1940. Inbreeding (that is, the mating of closely related stock), followed by matings between unrelated families, parallels the production of hybrid corn, which greatly outyields its parent stock. The results of thus crossing inbred stock of two different breeds, as well as of the same breed, promise much.

The offspring of inbred families of the Single-Comb Rhode Island Red variety that we mated to inbred Single-Comb White Leghorns have steadily exceeded the average of the family-selected purebred parental strains by about 25 eggs a pullet during the first laying year. These in-crossbred pullets were relatively nonbroody; many crossbred pullets are excessively broody. Incrossbred pullets may be excellent layers, but their records do not exceed those of the best purebreds, and it remains to be determined whether they are consistently superior to all family-selected strains of purebred chickens.

Hatcherymen and poultrymen who raise chickens for meat may improve the quality of their breeding stock by selecting birds for three main characteristics—fast feathering, rapid growth, and superior conformation. This plan of selection, which begins with young chicks, does not affect egg production and does not greatly increase management costs.

Fast feathering is desirable partly because it reduces the number of pinfeathers in market birds. Indications of fast feathering in day-old chicks are the length and number of the wing-feather sheaths. The best chicks for broiler stock have well-developed primary feathers—the large outer wing feathers—and well-developed secondaries, which number six or more and lie next to the primaries. Slow-feathering chicks have fewer secondaries and primaries that are not so well developed. You can easily find the feather sheaths in the down at the outer edge of the wings. If you select chicks of the desired type for next year's breeding flock, you should raise them by themselves or mark them in some way, by a wing band or leg band, for instance.

You can best judge the ability of chickens to grow rapidly by their body weight when they are 1 to 2 months old. Those that have made the most satisfactory gains should be kept for the breeding flock. You can make another check for growth at the age of 5 months, when you can remove from the special group any birds that are below expectations.

Superior conformation for meat production is indicated by good development of the breast when chickens are about a month and a half old, and not later than 3 months. Because the breast meat is the most valuable part of a broiler, only birds with well-meated breasts should be kept for use as breeders.

In producing broilers, the practice of crossing certain breeds or varieties has been popular and successful. Crossbreds commonly produce more meat for feed consumed than the purebred parents, they feather more satisfactorily, and fewer die during the growing period. Crossbred pullets and hens, however, tend to be broody oftener than the parent stock. Birds from Barred Rock roosters and New Hampshire or Single-Comb Rhode Island Red females are especially popular for meat production. Cross-breeding is less widely used for laying stock, although one advantage in crossing between certain breeds is that one can identify the sex of chicks at hatching time because of differences in the down color or feathering. For this purpose, nonbarred red, buff, or black roosters and barred hens may be used, or roosters with gold in their plumage may be bred to silver females.

In experiments covering 3 years, we made two- and three-way crosses of Rhode Island Red, White Wyandotte, and Light Sussex. We found that the crossbred progeny generally outgrew standardbred Rhode Island Red pullets up to 10 and 20 weeks of age, and matured somewhat earlier. Those of the two-way cross were 6 to 10 percent more viable, and the progeny of the three-way cross were even better in this respect. The crossbreds were no better than standardbred stock, however, in annual egg production, egg weight, hatchability, and weight of mature birds.

We bred by genetic selection a strain of rapid-feathering and fast-growing silver chickens with Columbian pattern from the offspring of these crosses. This strain now breeds true in major characteristics. After a few more years of improvement in egg production and meat type, it will be useful for broiler production. Its advantage over good rapid-feathering Barred Plymouth Rocks is that the progeny of Columbian males in both pure matings and crossbred matings with New Hampshire or Single-Comb Rhode Island Reds have light colored pinfeathers. Housewives accept the barred feathers of the purebred or crossbred progeny of Barred Plymouth Rock males as a mark of quality. Now that more broilers are marketed dressed, and often drawn and cut up ready to cook, the dark pinfeathers are a serious disadvantage.