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Sex-link
Sex-links are crossbred chickens whose color at hatching is differentiated by sex, thus making chick sexing an easier process. Sex-links come in several varieties. As hybrids of laying or dual-purpose breeds infused with extra vigor via heterosis, sex-links can be extremely good egg-layers which often produce 300 eggs a year or more depending on the quality of care and feed. The color of their eggs vary according to the mix of breeds, and blue-green eggs are possible. Chicks of a single breed that are similarly sex-linked are called autosex chickens, a term developed to differentiate between sex linkage in purebred chickens versus sex linkage in crossbreeds. Sex-link types Many common varieties are known as the black sex-link (also called black stars) and the red sex-link (also called red stars). More specific variety names are common as well. * Black sex-link like "Black rocks" are a cross between unique specially bred hybrid strains of Rhode Island Red rooster (but any no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Sex Linkage
Sex linkage describes the sex-specific patterns of inheritance and expression when a gene is present on a sex chromosome (allosome) rather than a non-sex chromosome ( autosome). Genes situated on the X-chromosome are thus termed X-linked, and are transmitted by both males and females, while genes situated on the Y-chromosome are termed Y-linked, and are transmitted by males only. As human females possess two X-chromosomes and human males possess one X-chromosome and one Y-chromosome, the phenotype of a sex-linked trait can differ between males and females due to the differential number of alleles (polymorphisms) possessed for a given gene. In humans, sex-linked patterns of inheritance are termed X-linked recessive, X-linked dominant and Y-linked. The inheritance and presentation of all three differ depending on the sex of both the parent and the child. This makes sex-linked patterns of inheritance characteristically different from autosomal dominance and recessiveness. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
ZW Sex-determination System
The ZW sex-determination system is a chromosomal system that determines the sex of offspring in birds, some fish and crustaceans such as the giant river prawn, some insects (including butterflies and moths), the schistosome family of flatworms, and some reptiles, e.g. majority of snakes, lacertid lizards and monitors, including Komodo dragons. It is also present in some plants, where it has evolved independently on many occasions, characterizing at least 22% of plants with documented sex chromosomes. The letters Z and W are used to distinguish this system from the XY sex-determination system. In the ZW system, females have a pair of dissimilar ZW chromosomes, and males have two similar ZZ chromosomes. In contrast to the XY sex-determination system and the X0 sex-determination system, where the sperm determines the sex, in the ZW system, the ovum determines the sex of the offspring. Males are the homogametic sex (ZZ), while females are the heterogametic sex (ZW). The Z ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Chick Sexing
Chick sexing is the method of distinguishing the sex of chickens and other hatchlings, usually by a trained person called a chick sexer or chicken sexer. Chicken sexing is practiced mostly by large commercial hatcheries to separate female chicks or "pullets" (destined to lay eggs for commercial sale) from the males or " cockerels" (most of which are killed within days of hatching because they are irrelevant to egg production). The females and a limited number of males kept for meat production are then put on different feeding programs appropriate for their commercial roles. Different segments of the poultry industry sex chickens for various reasons. In farms that produce eggs, males are unwanted; for meat production, separate male and female lines for breeding are maintained to produce the hybrid birds that are sold for the table, and chicks of the wrong sex in either line are unwanted. Chicks of an unwanted sex are killed almost immediately to reduce costs to the breeder. Meth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
White Rock (chicken)
The Plymouth Rock is an American breed of domestic chicken. It was first seen in Massachusetts in the nineteenth century and for much of the early twentieth century was the most widely kept chicken breed in the United States. It is a dual-purpose bird, raised both for its meat and for its brown eggs. It is resistant to cold, easy to manage, and a good sitter. History The Plymouth Rock was first shown in Boston in 1849, but was then not seen for another twenty years. In 1869, in Worcester, Massachusetts, one D.A. Upham cross-bred some Black Java hens with a cock with barred plumage and a single comb; he selectively bred for barred plumage and clean (featherless) legs. His birds were shown in Worcester in 1869; the modern Plymouth Rock is thought to derive from them. Other people have been associated with the development of the Plymouth Rock, as have other chicken breeds including the Brahma, the Cochin (both white and buff), the Dominique and the White-faced Black Spani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Heterosis
Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of any biological quality in a hybrid offspring. An offspring is heterotic if its traits are enhanced as a result of mixing the genetic contributions of its parents. The heterotic offspring often has traits that are more than the simple addition of the parents' traits, and can be explained by Mendelian or non-Mendelian inheritance. Typical heterotic/hybrid traits of interest in agriculture are higher yield, quicker maturity, stability, drought tolerance etc. Definitions In proposing the term heterosis to replace the older term heterozygosis, G.H. Shull aimed to avoid limiting the term to the effects that can be explained by heterozygosity in Mendelian inheritance. Heterosis is often discussed as the opposite of inbreeding depression, although differences in these two concepts can be seen in evolutionary considerations such as the role of genetic variation or the effects of genetic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Barred Rock
The Plymouth Rock is an American breed of domestic chicken. It was first seen in Massachusetts in the nineteenth century and for much of the early twentieth century was the most widely kept chicken breed in the United States. It is a dual-purpose bird, raised both for its meat and for its brown eggs. It is resistant to cold, easy to manage, and a good sitter. History The Plymouth Rock was first shown in Boston in 1849, but was then not seen for another twenty years. In 1869, in Worcester, Massachusetts, one D.A. Upham cross-bred some Black Java hens with a cock with barred plumage and a single comb; he selectively bred for barred plumage and clean (featherless) legs. His birds were shown in Worcester in 1869; the modern Plymouth Rock is thought to derive from them. Other people have been associated with the development of the Plymouth Rock, as have other chicken breeds including the Brahma, the Cochin (both white and buff), the Dominique and the White-faced Black Spani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
ISA Brown
The ISA Brown is a crossbreed of chicken, with sex-linked coloration. It is thought to have been the result of a complex series of crosses including but not limited to Rhode Island Reds and Rhode Island Whites, and contains gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...s from a wide range of breeds, the list of which is a closely guarded secret. It is known for its high egg production of approximately 300 eggs per hen in the first year of laying. History ISA stands for Institut de Sélection Animale, the company which developed the crossbreed in 1978 for egg production as a battery hen. In 1997, the ISA Group merged with Merck & Co., forming Hubbard ISA, so the variety is sometimes called Hubbard Isa Brown. In 2005, Institut de Sélection Animale (ISA) and Hendrix ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Delaware (chicken)
The Delaware is an American breed of chicken with an unusual plumage pattern. It was developed in the state of Delaware in the mid-twentieth century, and was initially known as the Indian River. It was briefly of some importance in the American chicken industry, until it was superseded by the common industrial Cornish Rock cross. In the twenty-first century it is an endangered breed. It may be kept for meat, for eggs or for showing. History In the early twentieth century, the cross of a Barred Plymouth Rock rooster on a New Hampshire hen was a common choice for producing broilers. Occasionally, this mating produces sports with light coloration. George Ellis of Delaware selectively bred these light-colored birds, which led to the creation of the breed in 1940. He first chose to call them ''Indian Rivers'', but later the name was switched to match its state of origin. At the time, the Delmarva Peninsula, where the breed was created, supplied chicken to the entirety of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Pullet
The chicken (''Gallus gallus domesticus'') is a domesticated subspecies of the red junglefowl (''Gallus gallus''), originally native to Southeast Asia. It was first domesticated around 8,000 years ago and is now one of the most common and widespread domesticated animals in the world. Chickens are primarily kept for their meat and eggs, though they are also kept as pets. As of 2023, the global chicken population exceeds 26.5 billion, with more than 50 billion birds produced annually for consumption. Specialized breeds such as broilers and laying hens have been developed for meat and egg production, respectively. A hen bred for laying can produce over 300 eggs per year. Chickens are social animals with complex vocalizations and behaviors, and feature prominently in folklore, religion, and literature across many societies. Their economic importance makes them a central component of global animal husbandry and agriculture. Nomenclature Terms for chickens include: * ''Bid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Red Shaver
The Red Shaver is a sex linked breed of chicken developed in Canada. Pullets are reddish-brown in colour with white underfeathers, while males are white with a few red markings on the feathers. They are a hardy, dual-purpose breed laying brown eggs and dressing out between three and five pounds. They have a reputation of being a quiet breed. Red Shaver chickens are used most frequently in small flocks for small farms. Eggs Red shaver hens can lay from 305 to 315 eggs a year, and are reported to be prolific producers of large brown eggs. One four-year-old Red Shaver chicken in Ottawa was credited with laying an egg with a mass of 143 grams, which is almost three times the size of a standard medium egg (Typically a medium egg is 49 g, a jumbo egg is 70 g).https://www.cbc.ca/news/canada/ottawa/giant-egg-laid-by-ottawa-hen-1.775106. Meat Body weight at 18 weeks is about 3 lbs., and after one year of laying weight between 4 to 5 lbs. See also * List of chicken breeds Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Wyandotte (chicken)
The Wyandotte is an American breed of dual-purpose chicken, raised both for its brown eggs and for its yellow-skinned meat. It was developed in the 1870s, and was named for the indigenous Wyandot people of North America. It has many color variants, and is also kept for showing. It was originally known as the American Sebright. History The Wyandotte was created in the United States in the 1870s by four people, H. M. Doubleday, John Ray, L. Whittaker and Fred Houdlette. The first type was the silver-laced, which was included in the ''American Standard of Perfection'' of the American Poultry Association in 1883; it was taken to Britain at about the same time. It had previously been known as the Sebright Cochin or American Sebright. The origin of the breed is unknown; it is thought derive partly from spangled Hamburgs and dark Brahmas – the Hamburg for the rose comb and the Brahma for the color pattern. The gold-laced variant was produced by breeding silver-laced hens with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
