The Dollar Hen Part 24

Unintelligent inbreeding as practiced on many a farm, results in run down stock, not so much from inbreeding as from lack of selection.

Out-crossing or mixing in of new blood is better than hit-or-miss inbreeding. Intelligent inbreeding is better still.

Scientific Theories of Breeding.

The main tenet of Darwin's theory of racial inheritance or evolution, was that changes in animal life, wild or domestic, were brought about by the addition of very slight, perhaps imperceptible, variations. He argued that the giraffe with the longest neck could browse on higher leaves in time of drought and hence left offspring with slightly longer necks than the previous generation.

Upon this theory the ordinary breeding by selection is based. In case of breeding for show room, the breeder's eye, or the judge's score card, is the tape with which to measure the length of the giraffe's neck. This principle can be applied equally well, even better, to characteristics where accurate measurement may be used.

The last forty years of scientific progress has established firmly the general theories of Darwin, but they have also resulted in our questioning his idea that all great changes are due to the sum of small variations. Many instances have been suggested in which the theory of gradual changes could not explain the facts.

The theory of mutation, of which Hugo de Vries, of Holland, is the chief expounder, does not antagonize Darwin, but simply gives more weight in the process of evolution to the factor of sudden changes commonly called sports. Let us ill.u.s.trate: In the giraffe of our former forest, one might appear whose neck was not longer because of slightly longer vertebrae, but who possessed an extra vertebrae.

This would be a mutation. In other words, a mutation is a marked variation that may be inherited. We now believe that polled cattle, five-toed Dorkings, top-knotted Houdans, frizzles and black skinned chickens arose through mutations.

Burbank's Methods--The wonderful Burbank with his thornless cactus, his stoneless plum, and his white blackberry, is simply a searcher after mutations. His success is not because he uses any secret methods, but because of the size of his operations. He produces his specimens by the millions, and in these millions looks, and often looks in vain for the lonely sport that is to father a new race.

Burbank has, with plants, many advantages of which the animal breeder is deprived. He can produce his specimens in greater number, he can more easily find out the desirable character, and in many plants he has not the uncertain element of double parentage to contend with, while with others he is still more fortunate, as he can produce them by seed, stimulate variation until the desired mutation is found and can then reproduce the desired variation with certainty by the use of cuttings. This latter is not true inheritance with its inevitable variation, but the indefinite prolongation of the life of one individual. In this sense there is only one seedless orange tree in the world.

The Centgenitor System--Prof. Hays in breeding wheat at Minnesota, first used in this country a system of breeding which is essentially as follows: A large variety of individual seeds are selected. These are planted separately and the amount and character of the yield observed. The offspring of one seed is kept separate for several generations, or until the character of the tribe is thoroughly established. The advantage of this plan of breeding is in that the selection is not made by comparing individuals, but by comparing the offspring of individuals. Thus, we necessarily select the only trait really worth while; that is prepotency or the ability to beget desirable qualities.

The application of this centgenitor system necessitates inbreeding; it also necessitates large operations. Of the former, breeders have generally been afraid; of the latter they have lacked opportunity.

But the centgenitor system, combined with Burbank's principle of large opportunity of selection, is, in the writer's belief, the method by which the 200-egg hen will be ultimately established in America.

Much of the recent stimulus to the study of the Science of Breeding was occasioned by the discovery of Mendel's Law. Briefly, the law states that when two pure traits or characters are crossed, one dominates in the first generation of offspring--the other remaining hidden or recessive. Of the second generation, one-half the individuals are still mixed, bearing the dominant characteristic externally and the other hidden; one-fourth are pure dominants and one-fourth are pure recessives. In future generations the mixed or hybrid individuals again give birth to mixed and pure types apportioned as before, thus continuing until all offspring become ultimately pure. For ill.u.s.tration: If rose and single comb chickens are crossed, rose combs are dominant. The first generation will all have rose combs. The second generation will have one-fourth single combs that will breed true, one-fourth rose combs that will breed rose combs only, and one-half that again will give all three types.

Mendel's Law works all right in cases where pure unit characteristics are to be found. For the great practical problems in inheritance, Mendel's law is utterly hopeless. The trouble is that the chief things with which we are concerned are not unit characteristics but are combinations of countless characteristics which cannot be seen or known, hence cannot be picked out. Thus the tendency to revert to pure types is foiled by the constant recrossing of these types.

Mendel's law is a scientific curiosity like the aeroplane. It may some day be more than a curiosity, but both have tremendous odds to overcome before they supplant our present methods.

Prof. C.B. Davenport, of the Carnegie Inst.i.tute, is working on experimental poultry breeding in its purely scientific sense. His conclusions have been much criticised by poultry fanciers. The truth of the matter is that the fancier fails to appreciate the spirit of pure science. The scientist, enthused to find his white fowl re-occur after a generation of black ones, is wholly undisturbed by the fact that the white ones, if exhibited, might be taken for a Silver Spangled Hamburg.

Mendel's law as yet offers little to the fancier and less to the commercial poultryman. Its study is all right in its place, but its place is not on the poultry plant whose profits are to buy the baby a new dress.

Breeding for Egg Production.

Attempts to improve the egg-producing qualities of the hen date from the domestication of the hen, but it has only been within the last few years that rapid progress has been possible in this work. The inability to determine the good layers has been the difficulty.

The great majority of people make no selection of hens from which to hatch their stock. The eggs of the whole flock are kept together and when eggs are desired for hatching they are selected from a general basket. It has been a.s.sumed, and is shown by trap-nest records, that eggs thus selected in the spring of the year are from the poorer, rather than from the better layers. This is because hens that have not been laying during the winter will lay very heavily during the spring season. Many breeders have attempted to pick out the good layers by the appearance of the hens. Before the advent of the trap-nest the "egg type" of hen was believed to be a positive indication of a good layer. The "egg type" hen had slender neck, small head, long, deep body of a wedge shape. Various "systems"

founded on these or other "signs" have been sold for fancy prices to people who were easily separated from their money. Trap-nest records show such systems to be on a par with the lunar guidance in agricultural operations.

I might remark here that the determination of s.e.x by the shape of the egg or similar methods, is in a like category. Science finds no proof of such theories.

A few methods of selecting the layers have been suggested which, while far from absolute, are of some significance and are well worth noting. The hen that sits upon the roost while other hens are out foraging, is probably a drone. The excessively fat or the excessively lean hens are not likely to be layers. It would naturally be supposed that the active laying hen would be the last one to go to roost at night. At the Kansas Experiment Station, the writer made observations upon the order in which the hens went to roost, and the above a.s.sumption was found in the majority of cases to be correct.

A still better scheme of selecting layers is the practice of picking out the thrifty, quickly maturing pullets when they first begin to lay in the fall season. At the Maine Experiment Station, such a selection gave a flock of layers which averaged about one hundred and eighty eggs, when the remainder of the flock yielded only one hundred and forty.

Trap-nests devised to catch the hen that lays the egg are numerous in the market. A trap-nest to be successful, must not only catch the hen that lays, but must prevent the entrance of the other hens.

The more trap-nests that are provided, the less often they will require attention, but the more often the nests are attended the better for the comfort of the hens.

The use of trap-nests is expensive and cannot be recommended for the poultryman who must make every hour of time put on his chickens yield him an immediate income. Fanciers and Experiment Stations can well afford to use trap-nests and must, indeed, use them both for breeding for egg production, and also for determining the hen that laid the egg when full pedigrees are desired in other breeding work.

A scheme that has sometimes been used in the place of trap-nests, is a system of small compartments, in each of which one hen is kept.

Such a scheme does not seem feasible on a large scale, but for breeders wishing to keep the records of a small number of hens, it is all right. Because of its cost, this system is wholly out of the question, except for a man following breeding as a hobby and who cannot devote himself during the day to the care of trap-nests.

Having determined the best layers, it remains to breed from these and from their descendants. The tests of pullets hatched from hens are better signs of the hen's value as a breeder than is her own record. It has been surmised that a hen which lays heavily will not lay eggs containing vigorous germs. So far as the writer's experience has gone, the laying of infertile eggs is a family or individual trait not particularly related to the number of eggs laid.

When we have bred from the best layers and have raised our average egg yielder to a higher level, the question arises as to whether the strain will permanently maintain the high yield or drop back to the former rate of production. Theory says that it will not drop back.

As a matter of fact it will not do so, for the heavier production will be more trying on the hen's const.i.tution, and naturally selection will gradually cause the egg record to dwindle. Hence the necessity of continued selection or the infusion of new blood from other selected strains.

Whatever may be the change desired in a strain of chickens, specimens showing the trait to be selected should be used as breeders. Those characteristics readily visible to the eye have long been the subjects of the breeder's efforts. But traits not directly visible can likewise be changed by breeding. The number of eggs, size and color of eggs, rapid growth, ready fattening powers, quality of meat and general characteristics, are all matters of inheritance, and if proper means are taken to select the desirable individuals all such characteristics can be changed at the will of the breeder.

It is a fact, however, often overlooked, that the more traits for which one selects, the slower will be progress. For ill.u.s.tration: If in breeding for egg production, one-half the good layers are discarded for lack of fancy points, the progress will be just half as rapid.

A discussion of the work in breeding for egg production at the Maine Experiment Station is taken up in the next chapter.

CHAPTER XV

EXPERIMENT STATION WORK

Our entire scheme of agricultural education and experimentation is new. The poultry work at experiment stations is very new. Ten years will about cover everything worthy of a permanent record in the poultry experiment station files.

Stations Leading in Poultry Work.

Among the earliest stations to begin poultry work in this country were Rhode Island, Ma.s.sachusetts, Connecticut and Maine. Rhode Island conducted the first school of poultry culture. The two stations of New York State were also early in the work, and Cornell now has the leading school of poultry culture in this country.

West Virginia has always maintained a considerable poultry plant.

Outside of the states east of the Appalachians, the first poultry work to be heard of was that of Prof. Dryden at the Experiment Station of Utah. Prof. Dryden's work was of a demonstrative nature.

His early bulletins were forceful and well ill.u.s.trated, and did much to call attention to poultry work.

In all this early work the great Mississippi Valley, where four-fifths of the nation's poultry is produced, entirely ignored the hen. The writer began his work with poultry at the Kansas Station in 1902, but his chickens were housed in a discarded hog house, and no funds being available, little was accomplished. In the last three or four years these experiment stations are rapidly falling into line and a number of poultry bulletins have recently been issued from these younger schools.

A few of the early landmarks in experiment station work was as follows:

The Utah Station clearly found that hens laid about 65 per cent. as many eggs in the second as in the first year, and that to keep hens for egg production beyond the second year, was unprofitable.

Ma.s.sachusetts proved that corn was a better food for layers than wheat, and that the prejudice against it was founded on a misapplied theory.

The New York Station at Geneva demonstrated that poultry generally, and ducks in particular, are not vegetarians, and must have meat to thrive and that vegetable protein will not make good the deficiency.

The Maine Station was chiefly instrumental in introducing trap-nests, curtain front houses and dry feeding. The breeding work at Maine will be discussed at length in the last section of this chapter.