| 词条 | Legbar |
| 释义 |
| name = Legbar | image = | image_size = | alt = Cream Legbar (young hen) | image_caption = | status = RBST (UK): watchlist | altname = | country = United Kingdom | distribution = | standard = | use = eggs | nickname = | apa = | aba = | ee = | pcgb = rare soft feather: light[1] | maleweight = 3.4 kg | femaleweight = 2.7 kg | skincolor = | eggcolor = Cream Legbar: blue or green Legbar: white or cream | comb = single | note = | type = Chicken | latin = Gallus gallus domesticus }} The Legbar is a rare British autosexing chicken breed. It was created in the early twentieth century by Reginald Crundall Punnett and Michael Pease at the Genetical Institute of Cambridge University. It was created by cross-breeding Barred Plymouth Rock chicken, Leghorns, Cambars, and in the case of Cream Legbars, Araucanas.[3] The Araucana blood in the Cream Legbar is reflected in its crest and blue to blue-green eggs.[4] HistoryThe Legbar was the second autosexing chicken breed created by Prof. Punnett and M. Pease at the Genetical Institute in Cambridge, after the Cambar, which was created in 1929 by crossing Barred Plymouth Rock with Gold Campine.[6][7] The aim was to create an autosexing utility breed with a focus on egg laying, where male and female day old chicks could easily be sexed by their colour. To achieve this Punnet and Pease used a crossing programme with excellent egg layers, the Leghorn and the Barred Plymouth Rock. The Barred Plymouth Rock was used to introduce the sex-linked barring gene ('barring' (B)) into the Leghorn. By crossing Brown Leghorn and Barred Plymouth Rock the Gold Legbar was created and standardised in 1945. The Silver Legbar followed in 1951. It had been created by crossing the Gold Legbar with White Leghorn and Silver Cambar.[3] The Cream Legbar were standardised in 1958 but nearly died out in the 1970s as blue eggs were not in demand. They were created by crossing Gold Legbar with White Leghorn and creme-coloured Araucana chicken. The Araucanas introduced the dilute creme gene ('inhibitor of gold' (ig)), as well as the crest and the blue eggs into this variety.[4] CharacteristicsThe appearance of the Legbar is similar to that of a barred Leghorn. The Cream Legbar possesses in contrast to the Gold Legbar and the Silver Legbar a crest due to its Araucana blood. The roosters weigh between 2,7 - 3,4 kg (6.0 - 7.5 lbs) and the hens weigh between 2,0 - 2,7 kg (4.4 - 6.0 lbs).[7] They are known to lay between 180 - 200 eggs per year.[3][4] The Legbar rooster is a muscular bird with a wedge shaped body which has a prominent breast and is wide at the shoulders but tapers slightly towards the root of the tail. It carries itself sprightly and alert. The back is long and flat while the moderately full tail is carried at 45°to the back. The large wings are carried tightly and well tucked up. The fine head has a strong yellow- or horn-coloured beak and a large erect bright red single-comb with five to seven even spikes. The crest of the Cream Legbar is small and compact and carried well back from the red or orange eyes, falling off the back of the head below the extended comb. The face is red and smooth with smooth and pendant cream or opaque white ear-lobes. The red wattles are long and thin and the neck is long and well feathered. The yellow legs are moderately long, strong, and free of feathers and the four toes are straight and well spread. The birds have a plumage of silky texture which is free from coarse or excessive feathers.[7] The female has general characteristics similar to that of the male, allowing for the natural differences between sexes. The single comb however can be either erect or falling gracefully over to either side of the face without obstructing the eyesight and the tail is carried at a lower angle. The crest of the female Cream Legbar is somewhat fuller and larger than that of the male, but should never be so full as to obstruct the eyes. The legs and feet of female Gold Legbars or Silver Legbars can be either yellow, orange or light willow.[7] Colours and varietiesThe Legbar has three colour varieties: Gold, Silver and Cream. The Cream Legbar has a crest and lays blue to blue-green eggs.[7] It is considered a rare breed by the Poultry Club of Great Britain, and falls under the Rare Poultry Society.[16]
The neck hackles of the female Gold Legbar are pale gold and barred with black. The breast is salmon and clearly defined from the dark smoky to slaty grey-brown body with light barring. The wings are a dark grey-brown, while the tail is dark grey-black with lighter broad bars. They lay white or creme-coloured eggs.[7]
The neck hackles of the female Silver Legbar are silver and barred with black. The breast is salmon and clearly defined from the silver-grey body with indistinct broad light barring. The wings are silver-grey, while the tail is also silver-grey with indistinct soft barring. They lay white or creme-coloured eggs.[7]
The neck hackles of the female Cream Legbar are cream, softly barred grey. The breast is salmon and clearly, while the body is silver-grey with indistinct broad soft barring. The wings are silver-grey, while the tail is also silver-grey with indistinct soft barring. The crest is cream and grey. They lay blue to blue-green eggs.[7] Today, several so-called Cream Legbars do not fulfil the breed standard of the Poultry Club of Great Britain because they have lost the dilute cream gene ('inhibitor of gold' (ig)).[4] The standards of the Bantam Legbars are similar to those of the large fowl. Males weight 850 g (30 oz) and females weight 620 g (22 oz).[7] AutosexingUnlike sex-linked hybrids, such as 'red sex-links' or 'black sex-links', the Legbar is an auto-sexing breed. Several other auto-sexing breeds or auto-sexing varieties of breeds exist, such as Plymouth Rock, Bielefelder Kennhuhn, Niederrheiner, and Norwegian Jærhøns. Most breeds that end with -bar, such as Welbar, Rhodebar, Brussbar or Wybar, are auto-sexing as well. The importance that auto-sexing plays in the Legbar breed is also reflected in the fact that, next to a standards for the adult birds, the down colour and patterns are also standardised.[7] Female Legbar chicks in general have a broad very dark brown stripe extending over the head, neck and rump and a clear eye barring. The edges of the stripe are clearly defined and should not be blurred and blending with the ground colour, which is dark brown. A light head spot should be visible but is usually small. The male Legbar chicks in contrast have a much paler down shade and the pattern is blurred and washed out from head to rump.[7] The marked difference between male and female chicks is due to gene dosage of the sex-linked barring gene ('barring' (B), 'nonbarring' (b+)).[7][25] This gene is located on the Z-Chromosome of birds. References1. ^1 [https://web.archive.org/web/20180612143235/http://www.poultryclub.org/img/Breed%20Classification.pdf Breed Classification]. Poultry Club of Great Britain. Archived 12 June 2018. [1][2][3][4][5][6][7][8]2. ^1 Francis H.A. Marshall, Edward Thomas Halnan (1946 [1920]). Physiology of farm animals, fourth edition. Cambridge: The University Press. {{nobreak|p. 270–71.}} 3. ^1 2 3 . Rare Breed Survival Trust. Accessed January 2016. 4. ^1 2 3 4 . Rare Breed Survival Trust. Accessed January 2016. 5. ^1 2 3 4 5 6 7 8 9 10 11 12 13 Victoria Roberts (2008). [https://books.google.com/books?id=nAfyUHY42u0C British poultry standards: complete specifications and judging points of all standardized breeds and varieties of poultry as compiled by the specialist breed clubs and recognised by the Poultry Club of Great Britain]. Oxford: Blackwell. {{ISBN|9781405156424}}. {{nobreak|p. 53-56}} 6. ^1 The Breeds We Cover. The Rare Poultry Society. Accessed August 2014. 7. ^1 2 {{cite journal |author=Hellström |title=Sex-linked barring in chickens is controlled by the CDKN2A/B tumour suppressor locus |journal=Pigment Cell & Melanoma Research |volume= 23 |issue=4 |pages=521–530 |year=2010 |pmid=20374521 |doi=10.1111/j.1755-148X.2010.00700.x|display-authors=etal}} Accessed January 2016. 8. ^1 {{cite journal|author=B. J. Dorshorst and C. M. Ashwell |title=Genetic mapping of the sex-linked barring gene in the chicken | journal=Poultry Science |volume=88 |issue=9 |pages=1811–1817 |year=2009 |pmid=19687264 |doi=10.3382/ps.2009-00134}} Accessed January 2016. }} External links
3 : Chicken breeds|Chicken breeds originating in the United Kingdom|Animal breeds on the RBST Watchlist |
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