Silkie

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This article is about a variety of chicken. For other uses, see Silkie (disambiguation).
Silkie
Silky bantam.jpg
A White Silkie hen
Other names Silky
Country of origin China
Traits
Skin color Black
Egg color Cream or tinted
Comb type Walnut
Classification
APA Asiatic
Chicken
Gallus gallus domesticus
Silkie eggs

The Silkie (sometimes alternatively spelled Silky) is a breed of chicken named for its atypically fluffy plumage, which is said to feel like silk. The breed has several other unusual qualities, such as black skin and bones, blue earlobes, and five toes on each foot, whereas most chickens only have four. They are often exhibited in poultry shows, and appear in various colors.

In addition to their distinctive physical characteristics, Silkies are well known for their calm, friendly temperament. Among the most docile of poultry, Silkies are considered an ideal pet. Hens are also exceptionally broody, and make good mothers. Though they are fair layers themselves, laying about three eggs a week, they are commonly used to hatch eggs from other breeds and bird species.

History

It is unknown exactly where or when fowl with their singular combination of attributes first appeared, but the most well documented point of origin is ancient China (hence another occasionally encountered name for the bird, Chinese silk chicken). Other places in Southeast Asia have been named as possibilities, such as India and Java.1 The earliest surviving written account of Silkies comes from Marco Polo, who wrote of a furry chicken in the 13th century, during his travels in Asia.2 In 1598, Ulisse Aldrovandi, a writer and naturalist at the University of Bologna, Italy, published a comprehensive treatise on chickens which is still read and admired today. In it, he spoke on "wool-bearing chickens" and ones "clothed with hair like that of a black cat".3

A Black Silkie hen and a non-Silkie chick. The breed is renowned for its broodiness and mothering abilities.

Silkies most likely made their way to the West via the Silk Route and maritime trade. The breed was recognized officially in North America with acceptance into the Standard of Perfection in 1874.1 Once Silkies became more common in the West, many myths were perpetuated about them. Early Dutch breeders told buyers they were the offspring of chickens and rabbits,2 while sideshows promoted them as having actual mammalian fur.4

In the 21st century, Silkies are one of the most popular and ubiquitous ornamental breeds of chicken. They are often kept as ornamental fowl or pet chickens by backyard keepers, and are also commonly used to incubate and raise the offspring of other chickens and waterfowl like ducks and geese and game birds such as quail and pheasants.1

A White Silkie rooster

Characteristics

Silkies are often mistakenly called a bantam breed, and although they are considered bantams in some countries, this varies according to region and many breed standards class them officially as large fowl; the bantam Silkie is actually a separate variety most of the time. Almost all North American strains of the breed are bantam sized, but in Europe the standard-sized is the original version. However, even standard Silkies are relatively small chickens, with the males weighing only four pounds (1.8 kg), and females weighing three pounds (1.36 kg).2 The American Standard of Perfection calls for males that are 36 ounces (1 kg), and females that are 32 ounces (910 grams).5

A Partridge Silkie hen

Silkie plumage was once unique among chicken breeds, however in recent years silkie feathering has been been developed in several breeds, mostly notably Chabo, where it is now standardised in Britain and the Netherlands.67 It has been compared to silk,8 and to fur. Their feathers lack functioning barbicels, and are thus similar to down on other birds and leave Silkies unable to fly. The overall result is a soft, fluffy appearance.9

Silkies appear in two distinct varieties: Bearded and Non-bearded. Bearded Silkies have an extra muff of feathers under the beak area that covers the earlobes. They also are separated according to color. Colors of Silkie recognized for competitive showing include Black, Blue, Buff, Grey, Partridge, and White. Alternative hues, such as Cuckoo, Lavender, Red, and Splash also exist. The standards of perfection call for all Silkies to have a small Walnut Comb, dark wattles, and turquoise blue earlobes. In addition to these defining characteristics, Silkies have five toes on each foot. Other breeds which exhibit this rare trait include the Dorking, Faverolles, and Sultan.2

All Silkies have black skin, bones and grayish-black meat; their Chinese language name is wu gu ji (烏骨雞,10 literally "dark boned chicken"), meaning "black-boned chicken".8 Melanism which extends beyond the skin into an animal's connective tissue is a rare trait, and in chickens it is caused by fibromelanosis, which is a rare mutation believed to have begun in Asia. The Silkie and several other breeds descended from Asian stock possess the mutation.11 Disregarding color, the breed does not generally produce as much as the more common meat breeds of chicken.9

Silkies lay a fair number of cream-colored eggs, but production is often interrupted due to their extreme tendency to go broody; a hen will produce 100 eggs in an ideal year. Their capacity for incubation, which has been selectively bred out of most fowl bred especially for egg production, is often exploited by poultry keepers by allowing Silkies to raise the offspring of other birds. In addition to being good mothers, Silkies are universally renowned for their calm, friendly temperament. They do well in confinement, and interact very well with children. This docility can cause Silkies to be bullied by more active or aggressive birds when kept in mixed flocks.12

Bantams

The Silkie bantam is a miniature variety of the Silkie, which is similar to the large Silkie in almost every way, except for size. In some countries, the Silkie bantam is the only or more common variety of Silkie, such as North America, where the bantam variety is the most popular. However in Australia the Silkie bantam is almost unknown, despite being standardised.

In the American Standard of Perfection the standard male weight for the bantam Silkie is 1 kg (36 oz) and for the female, 907 g (32 oz).13 The Australian Poultry Standard and British Poultry Standard call for Silkie bantams much smaller; in the Australian Poultry Standard, the standard weights are 680 g (25 oz) for males and 570 g (20 oz) for females.14 The British standard weight for bantam Silkies is 600 g (22 oz) for males, and 500 g for females (18 oz).15

Polydactyly

Silkies are also known for their polydactyly, usually manifesting as an additional 1-2 digits in the foot. The genetic cause of this extra digit formation has been shown to be a SNP in a regulator of the SHH gene, called the ZPA Regulatory Sequence (ZRS).1617 This causes ectopic SHH expression in the anterior of the developing limb bud, leading to increased tissue growth and digits. Interestingly, whilst the feet of the Silkie display polydactyly, the wings have the standard tridactyly (three digit) arrangement. The Japanese Silkie initially develops additional digits in the wing as an embryo, but these are lost prior to hatching.18 The genetic cause behind Silkie polydactyly differs from those that cause polydactyly in the Dorking chicken breed, which is due to ectopic FGF4 expression in the AER, with ectopic SHH a secondary effect.19

In cuisine

Silkie soup sold in Bukit Batok, Singapore

The black meat of a Silkie is generally considered an unusual attribute in European and American cuisines.8 In contrast, several Asian cuisines consider Silkie meat a gourmet food. Chinese cuisine especially values the breed, but it is also a common ingredient in some Japanese, Cambodian, Vietnamese and Korean dishes. Areas where Chinese cuisine has been a strong influence, such as Malaysia, may also cook Silkie. As early as the 7th century, traditional Chinese medicine has held that chicken soup made with Silkie meat is a curative food.8 The usual methods of cooking include using Silkie to make broth, braising, and in curries. Traditional Chinese soup made with Silkie also uses ingredients such as wolfberries, Dioscorea opposita (white yam), orange peel, and fresh ginger.20 A few fusion restaurants in metropolitan areas of the West have also cooked it as a part of traditional American or French cuisine, such as in confit.8

See also

Footnotes

  1. ^ a b c (Ekarius 2007, p. 158)
  2. ^ a b c d (Graham 2006, p. 130)
  3. ^ (Smith & Daniel 1975, p. 49)
  4. ^ (Percy 2002, p. 37)
  5. ^ (Ekarius 2007, p. 159)
  6. ^ http://www.aviculture-europe.nl/nummers/12E02A04a.pdf
  7. ^ British Poultry Standards. John Wiley & Sons. 2009. p. 142. 
  8. ^ a b c d e (Louie 2007)
  9. ^ a b (Ekarius 2007, pp. 158–159)
  10. ^ Dunlop, Fuchsia (2003). Land of Plenty. W. W. Norton & Company. pp. 236, 372. ISBN 0-393-05177-3. 
  11. ^ "Genetic study of black chickens shed light on mechanisms causing rapid evolution in domestic animals". ScienceDaily. 22 December 2011. Retrieved 21 May 2014. 
  12. ^ (Graham 2006, p. 131)
  13. ^ "Bantam Silkie Standard". American Poultry Association. 
  14. ^ Australian Poultry Standard. Victorian Poultry Association. 1998. 
  15. ^ "British Poultry Standard for Silkies". Poultry Club of Great Britain. 
  16. ^ Dunn IC, Paton IR, Clelland AK, Sebastian S, Johnson EJ, McTeir L, Windsor D, Sherman A, Sang H, Burt DW, Tickle C, Davey MG (May 2011). "The chicken polydactyly (Po) locus causes allelic imbalance and ectopic expression of Shh during limb development". Developmental Dynamics 240 (5): 1163–72. doi:10.1002/dvdy.22623. PMID 21465618. 
  17. ^ Lettice LA, Horikoshi T, Heaney SJ, van Baren MJ, van der Linde HC, Breedveld GJ, Joosse M, Akarsu N, Oostra BA, Endo N, Shibata M, Suzuki M, Takahashi E, Shinka T, Nakahori Y, Ayusawa D, Nakabayashi K, Scherer SW, Heutink P, Hill RE, Noji S (May 2002). "Disruption of a long-range cis-acting regulator for Shh causes preaxial polydactyly". Proc Natl Acad Sci USA 99 (11): 7548–53. doi:10.1073/pnas.112212199. PMID 12032320. 
  18. ^ Arisawa K, Yazawa S, Atsumi Y, Kagami H, Ono T (January 2006). "Skeletal Analysis and Characterization of Gene Expression Related to Pattern Formation in Developing Limbs of Japanese Silkie Fowl". Journal of Poultry Science 43 (2): 126–134. doi:10.2141/jpsa.43.126. 
  19. ^ Bouldin CM, Harfe BD (May 2011). "Aberrant FGF signaling, independent of ectopic hedgehog signaling, initiates preaxial polydactyly in Dorking chickens". Developmental Biology 344 (1): 133–41. doi:10.1016/j.ydbio.2009.07.009. PMID 19616534. 
  20. ^ "Recipe: Black-Skinned Chicken Soup". The New York Times. January 17, 2007. Retrieved 2008-06-23. 

References

Further reading

External links