American Chicken Breeds

From SourceWatch
Jump to navigation Jump to search

American Chicken Breeds are defined by the Standard of Perfection. Although many are recognized, the major ones that "have to any extend contributed to the makeup of... commercial stock," are the White Leghorn, Rhode Island Red, White Plymouth Rock, Barred Plymouth Rock, White Wyandotte, New Hampshire, and Cornish.[1]

History

Roots of American Chicken Breeds

Chickens arrived in the U.S. prior to the founding of the United States. Ships brought chickens with them as food for crew and passengers and many that had not been eaten during the voyage were sold or traded at ports in the U.S., introducing new gene stock to U.S. chickens. No breeds existed but certain places are known for unique "styles" such as large reddish chickens in Rhode Island that were ultimately developed into the modern Rhode Island Red.[2] The breeding of Red chickens began around 1830 according to one source[3] but a second source dates it to the 1840s.[4]

A second important milestone came in the 1830s and 1840s when chickens were imported to the U.S. from Asia. They were called "Cochin Chinas," "Brahma Pootras," "Shanghais," and "Chittagongs."[5] Ultimately, the Shanghai breed was developed into modern day Cochins, the Brahma Pootras into Brahmas, and the Cochin Chinas into Langshans. All three Asiatic breeds grew to large sizes and were well adapted to confinement.[6][3]

Other chickens that were imported included Javas in 1835,[3] Dorkings in 1841,[3], and Houdans in 1859.[7]

In 1847, Dominiques and Javas crossed, "providing the foundation for the development of Barred Rocks."[8] The Plymouth Rock breed, often seen in the Barred variety and referred to as the Barred Rock, was ultimately developed in 1856[7] and first exhibited in a show in 1869 by Rev. D.A. Upham of Connecticut.[7]

According to one source, another important breed, the White Leghorn, was first record in the U.S. in 1853.[8] Another source says that the name Leghorn was not given to an egg-producing variety previously referred to as an "Italian" chicken until the 1860s.[6]

Ascendancy of Chicken Shows and Advances in Breeding

On November 15, 1849, the first chicken show is held in Boston. More than 10,000 people attend and chicken shows become popular.[9] Chicken shows were soon popular, and breeders sought to produce chickens with perfect plumage and form that could win prizes in the showroom. Little attention was paid to other qualities of the chickens, like the number or size of the eggs the birds laid.

In 1860, the toe-punch was introduce to help breeders distinguish one chicken from another by the combinations of small holes punched in their toes.[10] A second innovation to aid in breeding, the trap nest, came along later. The first trap nest was patented in 1869[11] but the first "satisfactory" trap nest was not made until 1898.[12]. The trap nest allowed breeders to hold a hen in a nest after she laid her egg so they could tell which hen laid which egg.

Standardization of Breeds

American chicken breeds were not standardized until 1874, when the American Poultry Association published the Standard of Excellence, its official guidebook for poultry judging in North America.[13] The move to standardize breeds became necessary to facilitate the popular chicken shows.

Breed standardization began in the UK, when the London Poultry Club compiled standards for breeds of chickens in 1865-1866.[14] An American edition of the British Standard of breeds was published by A.M. Halsted in 1867.[14] Halsted published a second edition in 1871, but due to dissatisfaction with Halsted's version, W.H. Lockwood published a different Standard that same year.[14]

In 1873, American Poultry Association was established "to prepare and authorize a Standard breeding guide."[11] It did so the following year, titling it the Standard of Excellence. The first Standard contained 46 breeds. The second edition, published in 1875, contained 79 breeds and varieties.[13] In 1898, the name of the Standard of Excellence was changed to the Standard of Perfection, and it has kept that name ever since.[13]

Development of Popular Breeds

During this period, several new breeds were developed, including the Black Jersey Giant in 1870,[11] and the Silver-Laced Wyandotte during the 1870s.[15] However, the latter was initially called a Sebright Cochin until it was renamed in 1883.

White Plymouth Rocks were introduced in 1875.[16] Rhode Island Reds become popular in the 1890s[4] but were not admitted to the Standard until 1904.[4] All of the major breeds used commercially except the New Hampshire (which was admitted to the Standard in 1935) were developed prior to the 20th century.[17]

Beauty vs. Utility

According to one source, "Poultry raisers begin to show interest in egg numbers and quality, in addition to feather color and confirmation" beginning in 1870.[11] Another source dates the shift to the early 1900s.[18] A third wrote: [19]

"Breeding of poultry previous to the twentieth century was done by the fanciers who were interested primarily in the show ring qualities of their birds. The fanciers gave little consideration to the utilitarian qualities and, in some instances, established standards which were inimical to the bird's well being and productive performance. Certain standards for body shape, comb size, and even feather color tended to handicap the bird's reproductive capacity."

Certainly the beginning of the shift occurred by 1893:

"One of the earliest publications (1893) by an agricultural college reporting the results of studies on poultry breeding came from Professor Cushman of the Rhode Island Agricultural Experiment Station.[20] He reported the results of crossing several breeds of chickens on their reproductive qualities."[21]

Around this time, land grant universities and state experiment stations began breeding for utility, as did the hatcheries that were popping up and selling day-old chicks for less than breeders charged customers for fertile eggs to hatch at home. Breeders tended to prioritize qualities that would help a chicken win in a show, whereas hatcheries (like the land grant universities and experiment stations) focused on utility factors like egg production. Due to the conflict, breeders initially opposed hatcheries. However, strong opposition to hatcheries' practice of selling day-old chicks ended in 1913.[22]

The text from a 1919 course on poultry husbandry's lessons on breeding seems to split the difference between the preference for beauty or utility:[23]

"The business world is demanding efficiency in every line of work. The slacker is despised and unwelcome. The world demands the highest degree of production, and the poultry and egg business is no exception.
"It is true that the American Standard of Perfection, which is the guide for all breeder of pure bred poultry in selecting and judging their fowls, has many defects, yet a great variety of beautiful, thoroughbred fowls have been created and improved by the use of this Standard. The Standard bred fowl is the foundation upon which the whole poultry industry rests...
"As far as meat is concerned, the Standard for poultry speaks in many places of "rather long and broad back," "rather deep and full breast," "long keep bone and large thighs," "long, deep, full body which extends well forward," "luster to plumage," and other requirements for different varieties, none of which can be obtained only through careful selection and breeding, and through birds of the highest vitality. Certainly in the face of such Standard descriptions, no one can dispute the fact that there are utility qualities in the Standard bred poultry. Three thousand poultry buyers and fattening stations, in Missouri and other states, have all testified in writing to the fact that the pure bred bird is superior to any other for market purposes. The meat on a chicken is bred on, and is not altogether a question of feeding. [emphasis added]
"The thing in which we are lacking most in our Standard fowl is egg production. This is not due to any fault of the Standard fowl, but is due to the lax methods of the breeders themselves. On one side, we have the utility man who is too much inclined to disregard feathers on the legs, color of the plumage, and disqualifications of various sorts, just so long as his hens lay a large number of eggs. On the other hand, we have the extreme fancier who does not care whether his hen lays an egg or not, or what size, color and shape the egg is so long as the bird is able to win a prize in some show room. Both of these classes are in the wrong. We should not allow the pendulum to swing too far in either direction. Beauty and egg production can be and should be combined in the same fowl to the largest possible degree. There is a common ground upon which all poultrymen must meet if our industry is to prosper and the poultry business is to command the respect of the commercial and live stock world." [emphasis added]

At the time of the book's publication, standard breeds had existed for less than 50 years, and many farmers kept "mongrel" or "scrub" chickens that were not pure bred breeds. (The author says, "If there is a single logical reason why a single scrub hen should be tolerated on a single farm in this broad land of ours, I have been unable to locate it."[24]) While the previous section of the book shows a clear preference for standard breeds over mongrel chickens. It also displays a value on aesthetic qualities of chickens in addition to utilitarian factors. Later, it compares a chicken to a machine:[25]

"The hen, in a sense, is nothing more or less than a manufacturing plant. We feed her all she is able to consume, she takes what is needed for her own bodily maintenance and she either converts the surplus into eggs or stores it up in her body in the shape of fat and flesh. If she is properly bred, she will convert this surplus into a profitable number of eggs above the cost of her keep. Some hens have a greater capacity than others for the consumption of raw material, food, and a greater ability for manufacturing the finished product, eggs. Some flour mills have the capacity and ability to produce 100 barrels of flour per day and other mills which look just like them have the capacity to manufacture 1000 barrels per day. The difference is due to the machinery on the inside and to the management. The same principal [sic] applies in the case of the hen and in feeding her for egg production. If she hasn't the digestive organs to consume and digest larger quantities of feed, if she hasn't the efficiency and vitality coursing through her veins, she is not going to prove to be a profitable fowl. If the average hen at present lays 100 eggs per year, and we can increase the average to 150 eggs by a little more careful selection and breeding, we would thereby make an increase of 50%, and at no increase in the way of investment, labor, feed, equipment, or otherwise. This extra 50% is largely profit, and is just the difference between success and failure."

Breeding Shifts from the Public to the Private Sector

Ultimately, utility won out. "The agricultural experiment stations connected with various state agricultural colleges... led in the emphasis on economic traits in breeding programs."[26] Initially, these public sector institutions led the way in converting poultry breeding to a scientific endeavor. In addition to the 1893 research in Rhode Island noted above, G.M. Gowell carried out a long-term experiment using mass selection at the University of Maine in 1902. Later work at the Oregon Agricultural Experiment Station by James Dryden in 1921 "showed that mass selection could be effective in the early stages of breeding" for improvement in egg production. In these early years, breeders focused on dual-purpose breeds like the Plymouth Rock and Rhode Island Red because farmers preferred them to Leghorns, which produced more eggs but were not valuable for meat. Experiment stations began adding poultry geneticists to their staffs in 1907, and by 1940 nearly all had one in their employ.[27]

Early on, "some agricultural colleges sold breeding stock to poultry producers, however, most workers at the state institutions soon realized that they could make a greater contribution to the industry by concentrating efforts on solving basic breeding problems. Therefore, but few agricultural colleges have produced strains of poultry which have played an important role in poultry improvement." The exceptions were the Massachusetts Agricultural Experiment Station, which bred Rhode Island Reds, and the Oregon Agricultural Experiment Station, which produced a strain of Barred Plymouth Rocks that was "widely distributed" to farmers.[28]

A few breeders at the experiment stations attempted to understand poultry traits in terms of Mendelian genetics, but it turned out that the traits were controlled by many genes, making these attempts "unfruitful." The experiment stations did, however, debunk the common belief that pullets (hens under one year of age) should not be used as breeders because it would "adversely affect the vigor of the stock."[29] Universities also learned a great deal about the physiology of chicken reproduction to help advance breeding.[30]

A 1973 history of poultry summarized the role of universities as follows:[30]

"Over the past 70 years of poultry breeding there has been considerable change of agricultural experiment stations. First they served as a source of superior stocks of poultry. Then when private breeders became more numerous and took over the commercial distribution of chicks these institutions turned to refinement of the techniques of breeding.
"Now with the initiation of large breeding corporations, staffed with geneticists and equipped with the latest mechanized devices, there is no longer much dependence on the colleges for guidance. The state institutions can now turn to research of a more fundamental nature and to the training of geneticists."

The USDA also played some role. In 1925, Dr. Morley A. Jull of the USDA holds a Standardization Conference to draft a uniform plan to improve poultry breeding throughout the U.S. It is called the "Manhattan Plan."[31] However, another source states that "there was no well organized effort in breeding and genetics [by the federal government] until Dr. M.A. Jull brought Dr. C.W. Knox to the Federal Agricultural Research Center in 1931.[32] In 1935, the federal government adopted the National Poultry Improvement Plan, creating national standards for "certified" flocks. It mostly used the technique of mass selection, but it did "contribute to the improvement of poultry... primarily because of the expanse of its operation rather than the efficacy of the method.[33]

Advances in Assessing Egg Production

In addition to genetic advancements, an early challenge to breeders, even after the development of the trap nest, was the amount of labor it took to verify the number of eggs an individual chicken laid. There were attempts to create devices to remove the labor component - for example by fixing a stamp to the vent of a hen so that her band number was stamped on each egg as it came out - but none were successful.[34]

An early way to assess how many eggs a hen laid was the laying contest. One of the first such contests was at the Connecticut Agricultural College in 1911. By 1937, there were 17 such contests around the country. Each breeder would enter between 5 and 14 pullets that were already raised to maturity.[35] The contest would rear the pullets under the "best known management conditions" and record their egg laying performance. At first contests only recorded the number of eggs laid, but some of the highest numbers of eggs came from birds who laid small eggs. Later, eggs averaging 24 oz per dozen were given full points, with points deducted for smaller eggs. Most such contests came to an end by 1961, and the two remaining contests at that point ended after two more years.[36]

In 1949, California introduced the random sample test. By 1962, 22 other agricultural colleges were operating such tests. These tests used larger numbers of pullets than the laying contests, usually 50. The pullets were selected randomly as day-old chicks from commercial flocks. All chicks were hatched the same day and raised together under identical management.[37] The entries competed in profitability, not simply the number of eggs laid. They were measured on "income over feed and chick cost." By 1960, the USDA's Agricultural Research Service applied statistical analysis to the tests to correct for environmental differences and provide even more reliable results. Small breeders who had succeeded in the previous laying contests did not do as well in the random sampling tests; soon the random sampling tests were "dominated by the large corporations which used them primarily for advertising purposes." Only 10 such tests remained by 1970 and many of the large corporations had already dropped out.[38]

As the industry moved toward caging layers, it became easy for each individual producer to measure how much each hen laid. Therefore, large egg operations and large breeding corporations no longer needed public agencies to test their hens' egg production.[39]

Hybrids

The 1919 text on poultry husbandry quotes W.H. of the Reliable Poultry Journal at length in a section on Line breeding.[40] Card identifies cross breeding as the crossing of two chickens of different breeds and notes it is not the same as "hybridism," which he defines as an attempt at crossing two different species, such as mating a Guinea fowl with a chicken. He recommends line breeding as the best breeding strategy. He then refers to "outcrossing," or "The mating of females, that have been inbred or line bred, with a male of the same variety that is in no way related to the females."[41] He promises potentially positive results but advises caution:[41]

"This often results in increased vigor, increased size, increased flesh forming qualities, increased egg production, increased fertility and increase in length of life. Outcrosses should be made with great care. It is best to try the male on only a few of your females and see if the blood and the breeding of the male, dovetails, or mingles properly with that of the females for best results. When you discover such an outcross that is successful, it will pay you to retain the sire as long as his usefulness lasts."

Interestingly, Quisenberry himself, the author of the text, speaks out firmly against hybrids made by crossing two different breeds of chickens, saying "Crossing two pure-bred varieties is the first step toward creating a mongrel"[42] and "The whole idea of crossing two varieties to increase constitutional vigor is based on a fallacy."[43] As he sees it, the union of two chickens results in the average of the two, and the notion of hybrid vigor is a myth.

By 1910, Pearl and Surface published a comparison of crossbred chickens and their parent stocks.[44][45] Several more studies were published in the following decades.[46][47][48][49][50][51] Scientists looked at crosses between different strains within a breed and crosses between breeds. As of 1973, crosses of different strains of White Leghorns were favored despite findings favoring breed crossing because of "shell color problems."[52]

The Hy-Line International breeding organization, later called Pioneer Hi-Bred International, used corn breeding techniques on poultry. They did not start their commercial poultry operation until the 1940s, but founder Henry A. Wallace wrote letters about poultry genetics as early as 1928. When his son, H.B. Wallace, graduated from college in 1939, he took over the poultry breeding part of the operation.[53]

A second corn breeding company that played a major role in poultry was DeKalb Ag Research, beginning in 1944. They also applied corn techniques of crossing inbred lines to produce hybrid poultry. "By 1950 they had over 250,000 birds involved in their operations and began selling breeding stock throughout the world under a franchise system."[54]

A 1973 account of this part of history reads as follows:[55]

"A whole new era of poultry breeding was initiated when the largest hybrid corn breeders announced that they were starting poultry breeding projects.
"The Hy-Line Poultry Farms (associated with the Pioneer Hi-Bred Corn Company) placed 100,000 commercial chickens on the market in 1942 and was followed a few years later by the DeKalb Hybrid Seed Company. Each planned to use a breeding technique with chickens similar to that utilized so successfully in the production of hybrid corn.
"Previously numerous agricultural college workers had produced inbred lines and investigated the results of crossing them. Dunn (1923) Jull (1933)[47] and Maw (1942)[49] had reported results which were not very encouraging for producing hybrid chickens after the pattern for hybrid corn.
"Unfortunately these early studies were made on inbred lines of the same breed and sometimes the same strain. Also little consideration had been given to the reproductive performance of the strains producing the inbred lines. From these studies workers were not favorably impressed with the commercial possibilities of hybrid chickens, but apparently this belief was not shared by the hybrid seed corn producers since they started large scale programs with chickens.
"This technique involves the development of a large number of inbred lines of lines of poultry and crossing them to find the combinations which performs in a superior manner. The major problem here is to find the superior combinations and then to maintain the lines which have low vigor because of inbreeding.
"Commercial chicks produced by using the techniques of the corn breeders had a ready acceptance because of the phenomenal success of hybrid corn. A controversy arose regarding the use of the word hybrid in chick sales since the term had been previously used for breed crosses not involving inbreeding. IT required a ruling by the federal fair trade practice commission to settle the matter."

One other breeding technique that was used was called "reciprocal recurrent selection." Developed in the 1940s by corn breeders, a competition developed between advocates of breeding hybrids from inbred lines and advocates of reciprocal recurrent selection.[56][57] By 1973, both methods had produced "superior chicks" that had "competed successfully."[58]

Artificial Insemination

Artificial insemination was not practiced in a big way until the 1930s. By 1919, a text on poultry husbandry boasted (about artificial insemination) "We have been making some experiments along this line, and we have some living chicks which were hatched from eggs laid by hens that have never been allowed to run or come into contact with, or be treated by a male bird."[59] However, it then notes that, "Artificial fertilization may never be practical, but we learn other things as a result of work of this kind." The publication goes on to describe how to obtain semen from a male bird, by holding a hen and allowing the rooster to attempt to mate with her. As he did so, the person would slip a hand in between the male and the female and catch the semen either in the hand, a glass dish, or a rubber bag. Then the semen was inserted in the female with a medicine dropper.[60]

Articles and Resources

Related SourceWatch Articles

References

  1. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 249
  2. ↑ Skinner, J. L. (1974). Breeds: Early Breeders Built Foundations for Later Production Performance. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973. Madison, WI: American Printing and Publishing, Inc., p. 22
  3. ↑ 3.0 3.1 3.2 3.3 John L. Skinner, Hanke, O. A., & Florea, J. H. (Eds.). (1974). Chronology: American Poultry History People - Places - Progress U.S. and Canada. In American Poultry History 1823-1973 (pp. 680–741). Madison, WI: American Printing and Publishing, Inc., p 681.
  4. ↑ 4.0 4.1 4.2 Skinner, J. L. (1974). Breeds: Early Breeders Built Foundations for Later Production Performance. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973. Madison, WI: American Printing and Publishing, Inc., p. 39.
  5. ↑ Skinner, J. L. (1974). Breeds: Early Breeders Built Foundations for Later Production Performance. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973. Madison, WI: American Printing and Publishing, Inc., p. 25.
  6. ↑ 6.0 6.1 Skinner, J. L. (1974). Breeds: Early Breeders Built Foundations for Later Production Performance. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973. Madison, WI: American Printing and Publishing, Inc., p. 29.
  7. ↑ 7.0 7.1 7.2 John L. Skinner, Hanke, O. A., & Florea, J. H. (Eds.). (1974). Chronology: American Poultry History People - Places - Progress U.S. and Canada. In American Poultry History 1823-1973 (pp. 680–741). Madison, WI: American Printing and Publishing, Inc., p 683.
  8. ↑ 8.0 8.1 John L. Skinner, Hanke, O. A., & Florea, J. H. (Eds.). (1974). Chronology: American Poultry History People - Places - Progress U.S. and Canada. In American Poultry History 1823-1973 (pp. 680–741). Madison, WI: American Printing and Publishing, Inc., p 682.
  9. ↑ Skinner, J. L. (1974). Breeds: Early Breeders Built Foundations for Later Production Performance. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973. Madison, WI: American Printing and Publishing, Inc., p. 31.
  10. ↑ Skinner, J. L. (1974). Breeds: Early Breeders Built Foundations for Later Production Performance. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973. Madison, WI: American Printing and Publishing, Inc., p. 37.
  11. ↑ 11.0 11.1 11.2 11.3 John L. Skinner, Hanke, O. A., & Florea, J. H. (Eds.). (1974). Chronology: American Poultry History People - Places - Progress U.S. and Canada. In American Poultry History 1823-1973 (pp. 680–741). Madison, WI: American Printing and Publishing, Inc., p 684.
  12. ↑ Wilson, W. O. (1974). Housing: Environment Has Been Man’s Concern Ever Since the Hen’s Jungle Days. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 218–247). Madison, WI: American Printing and Publishing, Inc., pp. 235-236.
  13. ↑ 13.0 13.1 13.2 Skinner, J. L. (1974). Breeds: Early Breeders Built Foundations for Later Production Performance. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973. Madison, WI: American Printing and Publishing, Inc., p. 22
  14. ↑ 14.0 14.1 14.2 Skinner, J. L. (1974). Breeds: Early Breeders Built Foundations for Later Production Performance. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973. Madison, WI: American Printing and Publishing, Inc., p. 35.
  15. ↑ Skinner, J. L. (1974). Breeds: Early Breeders Built Foundations for Later Production Performance. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973. Madison, WI: American Printing and Publishing, Inc., p. 38.
  16. ↑ John L. Skinner, Hanke, O. A., & Florea, J. H. (Eds.). (1974). Chronology: American Poultry History People - Places - Progress U.S. and Canada. In American Poultry History 1823-1973 (pp. 680–741). Madison, WI: American Printing and Publishing, Inc., p 685.
  17. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 249
  18. ↑ Skinner, J. L. (1974). Breeds: Early Breeders Built Foundations for Later Production Performance. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973. Madison, WI: American Printing and Publishing, Inc., p. 45.
  19. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 248.
  20. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 257-259
  21. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 259
  22. ↑ Funk, E. M. (1974). Hatcheries: Commercial Hatcheries Provide Ready-made Farmer Egg Machines. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 162–183). Madison, WI: American Printing and Publishing, Inc., pp. 164-165.
  23. ↑ Quisenberry, T. E. (1919). The Principles of Mating and Breeding (Vol. 8 and 9). Kansas City, MO: The American School of Poultry Husbandry, p. 1.
  24. ↑ Quisenberry, T. E. (1919). The Principles of Mating and Breeding (Vol. 8 and 9). Kansas City, MO: The American School of Poultry Husbandry, p. 27.
  25. ↑ Quisenberry, T. E. (1919). The Principles of Mating and Breeding (Vol. 8 and 9). Kansas City, MO: The American School of Poultry Husbandry, p. 2.
  26. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 257
  27. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 259
  28. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 259
  29. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 260
  30. ↑ 30.0 30.1 Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 261
  31. ↑ Funk, E. M. (1974). Hatcheries: Commercial Hatcheries Provide Ready-made Farmer Egg Machines. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 162–183). Madison, WI: American Printing and Publishing, Inc., p. 170.
  32. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 268
  33. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 269.
  34. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 250
  35. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 265
  36. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 266.
  37. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 266
  38. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 267
  39. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 267.
  40. ↑ Quisenberry, T. E. (1919). The Principles of Mating and Breeding (Vol. 8 and 9). Kansas City, MO: The American School of Poultry Husbandry, p. 21-25.
  41. ↑ 41.0 41.1 Quisenberry, T. E. (1919). The Principles of Mating and Breeding (Vol. 8 and 9). Kansas City, MO: The American School of Poultry Husbandry, p. 24.
  42. ↑ Quisenberry, T. E. (1919). The Principles of Mating and Breeding (Vol. 8 and 9). Kansas City, MO: The American School of Poultry Husbandry, p. 27.
  43. ↑ Quisenberry, T. E. (1919). The Principles of Mating and Breeding (Vol. 8 and 9). Kansas City, MO: The American School of Poultry Husbandry, p. 28.
  44. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 264
  45. ↑ Pearl, R. and F.M. Surface, 1910. Studies on hybrid poultry. Maine Agr. Exper. Sta. Bull. 179.
  46. ↑ Don Cameron Warren, 1930. Crossbred Poultry. Kansas Agr. Exper. Sta. Bull. 252.
  47. ↑ 47.0 47.1 M.A. Jull, 1933. Inbreeding and intercrossing in poultry. J. Hered. 24:93-101.
  48. ↑ Knox, C.W., 1939. Crossbreeding in the domestic fowl. Proc. 7th Worlds Poul Congr. 58-71.
  49. ↑ 49.0 49.1 Maw, A.J.G., 1942. Crosses between inbred lines of the domestic fowl. Poultry Sci. 21:548-553.
  50. ↑ Hutt F.B., and R.K. Cole, 1952. Heterosis in an inter-strain cross of White Leghorns. Poultry Sci. 31:365-374.
  51. ↑ Nordskog, A.W., and F.J. Ghostley, 1954. Heterosis in Poultry 1. Strain crossing and crossbreeding compared with closed flock breeding. Poultry Sci. 33:704-715.
  52. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 264-265
  53. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 255-256
  54. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 256
  55. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 270-271
  56. ↑ Hull, F.H., 1945. Recurrent selection and specific combining ability in corn. J. Amer. Soc. Agron. 37: 134-135.
  57. ↑ Comstock R. E., H.F. Robinson, and P.H. Harvey, 1949. A breeding procedure designed to make maximum use of both general and specific combining ability. Agron. J. 41: 360-367.
  58. ↑ Warren, D. C. (1974). Breeding: Following Breeding by Selection New Methods Used Genetic Science. In John L. Skinner, O. A. Hanke, & J. H. Florea (Eds.), American Poultry History 1823-1973 (pp. 248–276). Madison, WI: American Printing and Publishing, Inc., p. 2271
  59. ↑ Quisenberry, T. E. (1919). The Principles of Mating and Breeding (Vol. 8 and 9). Kansas City, MO: The American School of Poultry Husbandry, p. 12.
  60. ↑ Quisenberry, T. E. (1919). The Principles of Mating and Breeding (Vol. 8 and 9). Kansas City, MO: The American School of Poultry Husbandry, p. 13.

External Resources

  • Morley A. Jull, Poultry Breeding, 1932.
  • F.A. Hays and G.T. Klein, Poultry Breeding Applied, 1943.
  • F.B. Hutt, Genetics of the Fowl, 1949.
  • Don Cameron Warren, Practical Poultry Breeding, 1953.

External Articles

Retrieved from "https://www.sourcewatch.org/index.php?title=American_Chicken_Breeds&oldid=694021"