Solid White (chicken Plumage)
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In
poultry Poultry () are domesticated birds kept by humans for the purpose of harvesting animal products such as meat, Eggs as food, eggs or feathers. The practice of animal husbandry, raising poultry is known as poultry farming. These birds are most typ ...
standards, solid white is coloration of
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
in
chicken 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 w ...
s ('' Gallus gallus domesticus'') characterized by a uniform pure white color across all
feather Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and an exa ...
s, which is not generally associated with depigmentation in any other part of the body. Color is an important feature of most living organisms. In the wild, color has great significance affecting the survival and reproductive success of the species. The environmental constraints which lead to the specific colors of birds and animals are very strong and individuals of novel colors tend not to survive. Under domestication, mankind has transformed all the species involved which have thus been freed from environmental pressures to a large extent. Early color variants were mostly selected for utility reasons or religious practices. In more recent centuries color varieties have been created purely for ornament and pleasure, fashion playing a surprisingly large part in their development. A bewildering array of colors and patterns can now be found in the domestic fowl. In the last decades white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color has become essential for the efficient processing of broilers and most types of meat-type poultry. Slaughterhouses and meat processing plants require poultry with a white or very light undercolor to produce carcasses without the typical "hair", which colored chickens have, that necessitates singeing after plucking. There are several chicken breeds having solid white as the most typical
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color, such as Leghorn,
Dorking Dorking () is a market town in Surrey in South East England about south-west of London. It is in Mole Valley, Mole Valley District and the non-metropolitan district, council headquarters are to the east of the centre. The High Street runs ro ...
,
Bresse Gauloise The Bresse Gauloise is a French breed of domestic chicken. It originates in the historic region and former province of Bresse, in the regions of Rhône-Alpes, Bourgogne and Franche-Comté, in eastern France. Because of legal restrictions on th ...
,
Polish Polish may refer to: * Anything from or related to Poland, a country in Europe * Polish language * Polish people, people from Poland or of Polish descent * Polish chicken * Polish brothers (Mark Polish and Michael Polish, born 1970), American twin ...
, Wyandotte and others. And there are many other breeds better known by their colored varieties, which also have a solid white variety, such as
Plymouth Rock Plymouth Rock is a boulder in Plymouth, Massachusetts, that symbolizes the historical disembarkation site of the '' Mayflower'' Pilgrims who founded Plymouth Colony in December 1620, and has been claimed to be the Pilgrims' actual landing site. ...
,
Orpington Orpington is a town in Greater London, England, within the London Borough of Bromley. It is 13.4 miles (21.6 km) south east of Charing Cross. On the south-eastern edge of the Greater London Built-up Area, it is south of St Mary Cray, sou ...
,
Rhode Island Red The Rhode Island Red is an American breed of domestic chicken. It is the state bird of Rhode Island. It was developed there and in Massachusetts in the late nineteenth century, by cross-breeding birds of Oriental origin such as the Malay wit ...
,
Jersey Giant The Jersey Giant is an American breed of domestic chicken. It was created in Burlington County, New Jersey, in the late nineteenth century. It is among the heaviest of all chicken breeds.Hutt, F.B. ''Genetics of the fowl''. McGraw-Hill Book Co. N.Y. 1949.Somes, R. G. ''International Registry of Poultry Genetic Stocks. A Directory of Specialized Lines and Strains, Mutations, Breeds and Varieties of Chickens, Japanese Quail and Turkeys''. Storrs Agricultural Experiment Station, The University of Connecticut, Storrs, Bulletin #460, (1981).


Description

Chicks down color of solid white chicken breeds can vary from a light creamy white, through different yellow shades, to a toasted orange. In adult phase, the entire surface of the
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
is pure white due to the absence of
melanin Melanin (; ) is a family of biomolecules organized as oligomers or polymers, which among other functions provide the pigments of many organisms. Melanin pigments are produced in a specialized group of cells known as melanocytes. There are ...
pigmentation in all parts of the
feather Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and an exa ...
s. The absence of
melanin Melanin (; ) is a family of biomolecules organized as oligomers or polymers, which among other functions provide the pigments of many organisms. Melanin pigments are produced in a specialized group of cells known as melanocytes. There are ...
in the
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
of solid white chicken breeds does not affect other body structures, except in the case of the albinos, which are easily recognized by their pink eye color.


History

Most chicken
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color genetic factors were manipulated during domestication by selection and crossings, which led to the modern chicken breeds, but there are no historical records of when or where the first chicken breeds with solid white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
arose. In the creation of new white breeds, white color have been sometimes introduced from breeds of solid white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
. Rhode Island White arose from the work of J. Alonzo Jocoy of Peacedale, Rhode Island, which began in 1888. Developed through crosses of Partridge
Cochin Kochi ( , ), formerly known as Cochin ( ), is a major port city along the Malabar Coast of India bordering the Laccadive Sea. It is part of the district of Ernakulam in the state of Kerala. The city is also commonly referred to as Ernaku ...
s, White Wyandottes, and the rose comb type of White Leghorn, it was solidified as a breed by 1903. And it was first accepted into the American Poultry Association's Standard of Perfection in 1922. Moderately popular up until the 1960s, it is now a relatively rare fowl. On the other hand, there is not a unique genetic mutation for solid white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color. There are two very well known autosomal major mutations leading to solid white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color, but also a number of complementary mutations properly combined may reduce or restrict pigment with a sufficient intensity to produce a final solid white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color, even in the absence of the major mutations for white. Most varieties of solid white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
chickens belong to some of the first two major mutations leading to solid white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color. These are commonly regarded as "dominant white" and "recessive white" according to the major mutation involved. The term "dominant white" has also been applied in genetic literature to a mutation producing white coat color in
horses The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 milli ...
. Four different recessive albino or albino-like mutations which also produce white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color in the chicken were also reported in literature, but those are not typical of any breed of chicken, and may be associated to a reduced perinatal viability or a deficient vision.


Dominant white

Dominant white was one of the first traits in aviculture which proved to be inherited according to the Mendelian laws, when in 1902 Bateson found that the cross of White Leghorns x Indian Games (or its reciprocal) gives F1 chicks with a white or a black spotted ashy white down. And that the F2 gives light and dark chicks in the 3:1 Mendelian proportion, which was confirmed by Hurst in 1905, Bateson and Punnet in 1906Bateson, W. and Punnet, R.C. 1906 Experimental studies in the physiology of heredity, Poultry. ''Repts. Evol. Comm. Roy. Soc.'' III, 11-30. and many others. The symbol ''I'' (inhibitor of black) to identify this mutation was introduced by Hadley in 1913. Although homozygotes ''I''/''I'' have always a solid white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color, heterozygous ''I''/''i''+ chicks are generally black spotted, while the presence of black or partially black feathers on a whitish adult
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
is very common.


Recessive white

Solid white varieties of
Dorking Dorking () is a market town in Surrey in South East England about south-west of London. It is in Mole Valley, Mole Valley District and the non-metropolitan district, council headquarters are to the east of the centre. The High Street runs ro ...
s,
Plymouth Rock Plymouth Rock is a boulder in Plymouth, Massachusetts, that symbolizes the historical disembarkation site of the '' Mayflower'' Pilgrims who founded Plymouth Colony in December 1620, and has been claimed to be the Pilgrims' actual landing site. ...
s, Wyandottes,
Minorca Menorca or Minorca (from , later ''Minorica'') is one of the Balearic Islands located in the Mediterranean Sea belonging to Spain. Its name derives from its size, contrasting it with nearby Mallorca. Its capital is Maó, situated on the is ...
s,
Orpington Orpington is a town in Greater London, England, within the London Borough of Bromley. It is 13.4 miles (21.6 km) south east of Charing Cross. On the south-eastern edge of the Greater London Built-up Area, it is south of St Mary Cray, sou ...
s and other breeds are regarded as recessive whites because their white is completely recessive to any other color. Both kinds of white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
: "dominant white" and "recessive white" are phenotypically identical in adult phase, and can only be distinguished from each other by means of a progeny test. In 1906 and 1908 Bateson and Punnet demonstrated that White Dorkings are homozygous for an autosomal recessive mutation which prevents appearance of color. They assigned to this mutation the symbol ''c'', as being recessive from the normal allele (''C''+, chromogen) which allows normal
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color development. This same kind of white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color was found by Bateson and Punnet in Rose Comb Bantam and in White Wyandotte. It was also found in White Cochin by Davenport in 1906, in White Langshan by Goodale in 1910, in White Plymouth Rock by Hadley in 1914, and in other breeds. "Recessive white" chickens may be potentially black barred or of some other color pattern, but does not reveal this, unless they are submitted to a progeny test. White Plymouth Rock chickens carry a considerable mixture of genes taken from other breeds different from the original Barred Plymouth Rock from which the white variety originates.


Albinism and partial albinism

Dominant and recessive major solid white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
varieties are not
albinos Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...
, but just white chickens in which
melanin Melanin (; ) is a family of biomolecules organized as oligomers or polymers, which among other functions provide the pigments of many organisms. Melanin pigments are produced in a specialized group of cells known as melanocytes. There are ...
is limited to eyes. In the ornithological literature there are many reports about totally or partially
albino Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...
birds, but most of them are not studied genetically. In 1933 Warren described in White Wyandotte a kind of complete
albinism Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...
caused by an autosomal recessive mutation to which he assigned the symbol ''a''. As the White Wyandotte birds were of a solid white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color,
albinos Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...
could only be recognized by the brilliant red of their eyes. Those
albinos Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...
had such a deficient vision that newborn chicks had difficulties to find the feeders, while adult females had difficulties to find the provided trap-nests . They were all very sensitive to sun light and preferred to remain indoors. Light microscopic histology of the retinal pigment epithelium of autosomal
albinos Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...
was done in the original study by Warren, but subsequent light or electron microscopic studies of autosomal
albino Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...
eyes or feathers have not been reported. The histology of the iris showed no evidence of pigmentation. At the ultra-structural level, small, spherical, poorly pigmented granules were seen in autosomal
albino Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...
retinal melanocytes. In 1940 Warren described a different autosomal recessive mutation known as "pink eye" (''pk'') that severely reduce pigmentation in the eyes, but only dilutes the pigment in the
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
, so this mutation does not produce a solid white color. The ultra-structure of "pink eye" melanocytes from both the eyes and feathers of embryo chicks and adults has been extensively defined. In 1941 Mueller and Hutt reported a sex-linked partial
albinism Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...
in Barred Plymouth Rock due to a simple sex-linked recessive mutation. The same mutation was later found in another flock of Barred Rocks and in White Leghorn. Affected birds had as good vision as normal ones. In 1983 Brumbaugh, Bargar and OettingBrumbaugh, J.A., Bargar, T.W. and Oetting, W.S. 1983 A "new" allele at the C pigment locus in the fowl. ''Journal of Heredity''. 74, 331-336. reported a third recessive allele at the ''C'' pigment locus, to which they assigned the symbol ''c''a. This allele in homozygous individuals produces a kind of partial
albinism Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...
. Concomitant electron microscope studies of both retinal and feather melanocytes showed that both mutant alleles ''c'' and ''c''a are citochemically tyrosinase negative, possess hypertrophied Golgi systems and contain numerous vesicles that appear to be incompletely formed, unpigmented granules. Retinal melanocytes possess a few pigmented granules, more in recessive white (''c'') cells than in
albino Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...
(''c''a) cells. At the ultra-structural level, small, spherical, poorly pigmented granules were seen in autosomal
albino Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...
retinal melanocytes. This explains the gradual but slight darkening of the eyes as a bird matures. Both variants are citochemically tyrosinase negative. Late embryonic mortality is higher in ''c''a/''c''a homozygous individuals.
Albinos Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...
exhibit shorter down length, reflecting a general state of immaturity and retardation of neonatal development, higher incidence of subcutaneous haemorrhage and inflammation, increased incidence of yolk sac protrusion and slower growth rate and smaller body size than colored chickens. Mortality in
albinos Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...
is also significantly higher, feed consumption and feed utilization is reduced. The numerous alterations associated with partial
albinism Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...
in the fowl are difficult to explain merely considering ''C'' locus only the structural gene of tyrosinase. This locus may provide broader regulatory function instead. In the opinion of the scientists, it may exist additional physiological functions for
melanin Melanin (; ) is a family of biomolecules organized as oligomers or polymers, which among other functions provide the pigments of many organisms. Melanin pigments are produced in a specialized group of cells known as melanocytes. There are ...
/functional tyrosinase that are not involved with pigmentation.


Genetics of solid white plumage

Inheritance of chicken
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color is complex. It depends on several genetic factors which interact epistatically. Genetic symbology for most color
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
mutations can be found in Hutt's classical book of poultry genetics published in 1949, in Abbott and Yee's Handbook published in 1975 and in Some's alphabetical list of genes issued in 1980.


Recessive white (''c'')

Solid white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
is the result of several combinations of genes which interact to give the final result. The expression of any color, except white, requires the presence of the normal allele ''C''+, an autosomic dominant allele that allows the synthesis of pigment in the feathers. ''C''+ is the most dominant of the allelic series of the locus ''C'' with the following order of dominance: ''C''+ (colored) > ''c'' (recessive white) > ''c''a (partial albinism) But ''C''+ is not completely dominant over ''c'' . In 1979 Carefoot found that in certain genetic backgrounds homozygous ''C''+/''C''+ can be distinguished from the heterozygous ''C''+/''c'' Recessive white is one of the two major causes of white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color. Most solid white chicken breeds are pure for recessive white ''c'' allele. ''c'' in homozygosity produces solid white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color in all individuals.


Dominant white (''I'')

A few breeds such as White Leghorn and
Hamburg Hamburg (, ; ), officially the Free and Hanseatic City of Hamburg,. is the List of cities in Germany by population, second-largest city in Germany after Berlin and List of cities in the European Union by population within city limits, 7th-lar ...
have a "dominant white" ''I'' mutation for
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color. This mutation selectively inhibits black color and dilutes red color in the feathers. So, it is also known as "inhibitor of black". It is less effective in heterozygotes, having poor effect on red but reducing black to just a few ticks and spots. In other words, homozygous ''I''/''I'' chickens have solid white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
regardless of the other major or complementary mutations present in the individuals, but without effect on the
melanin Melanin (; ) is a family of biomolecules organized as oligomers or polymers, which among other functions provide the pigments of many organisms. Melanin pigments are produced in a specialized group of cells known as melanocytes. There are ...
of the eye. "Dominant white" is also frequent in breeds which are habitually "recessive white", such as White Minorca, White Wyandotte and White Plymouth Rock. Heterozygous ''I''/''i''+ individuals show a drastic reduction of black in the
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
, but only a slight reduction of red pigment. While homozygous ''i''+/''i''+ individuals may be of any color if also carry the ''C''+ allele which allows the normal expression of color Because of the ineffectiveness of ''I'' to reduce red pigment, it can go unnoticed in breeds with buff
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color. In 1933 Danforth could extract the "dominant white" allele from Buff Leghorns and Buff
Minorca Menorca or Minorca (from , later ''Minorica'') is one of the Balearic Islands located in the Mediterranean Sea belonging to Spain. Its name derives from its size, contrasting it with nearby Mallorca. Its capital is Maó, situated on the is ...
s which showed no sign of having this mutation. As in both breeds it was not evident the presence of "dominant white" mutation, the results were completely unexpected until its revelation by the progeny tests. The presence of the "dominant white" from White Leghorn is due to previously made crossings with the intention to introduce some of the desirable qualities of this breed.


Disadvantages associated with recessive white

Since 1959 it had been reported that recessive white ''c'' allele in homocygosis significantly reduces body growth rate and body size in a magnitude of 4-10%. This was later confirmed in meat-type chickens by the researches of Fox and Smyth,Fox, W. and Smyth, J.R. Jr. 1985 The effects of recessive white and dominant white genotypes on early growth rate. ''Poult Sci.'' 64:429-433. and in egg-type breeds by the research of Mèrat and coworkers. This is a serious drawback to the poultry meat-type production which remains unsolved to the present day. A white or very light undercolor is essential for the efficient processing of broilers and decrepit layers in slaughterhouses and meat processing plants, however White Plymouth Rock, a typical "recessive white" breed, continues to be used as the female side of most commercial broiler crosses, while White Cornish continues to be used as the male side. As a result, most modern broiler chickens are homozygous ''c''/''c''. It is of importance to the meat breeding industry to know the magnitude of the depression in growth rate caused by the recessive white genotype in the commercial stocks. Also, several other pigment dilution genes, have been reported to depress growth rate. The experimental results of Fox and Smyth in 1985 also proved that ''c'' (recessive white) and ''I'' (dominant white) do not act in additive manner in influencing growth rate, and more importantly, the depression observed for "recessive white" was not enhanced by the presence of "dominant white" (''I''). As part of the future strategy of the genetic work on the parent stocks of the male side It would not be necessary to eliminate segregating "dominant white" from recessive white lines, but it would be economically advantageous to remove "recessive white" from the male lines.


White chicken breeds with "dominant white"

*
Brahma Brahma (, ) is a Hindu god, referred to as "the Creator" within the Trimurti, the triple deity, trinity of Para Brahman, supreme divinity that includes Vishnu and Shiva.Jan Gonda (1969)The Hindu Trinity, Anthropos, Bd 63/64, H 1/2, pp. 212– ...
, white,
regular and bantam * Belgian Bearded d'Anvers bantam, white *
Hamburg Hamburg (, ; ), officially the Free and Hanseatic City of Hamburg,. is the List of cities in Germany by population, second-largest city in Germany after Berlin and List of cities in the European Union by population within city limits, 7th-lar ...
white (a rare breed

* La Bresse * Leghorn chicken, Leghorn white; regular single-comb, bantam single-comb, and regular rose-comb *
Minorca Menorca or Minorca (from , later ''Minorica'') is one of the Balearic Islands located in the Mediterranean Sea belonging to Spain. Its name derives from its size, contrasting it with nearby Mallorca. Its capital is Maó, situated on the is ...
, white; single-
and rose-comb * Modern Game fowl, Modern Game, white, regular
and bantam * Polish chicken, Polish white; regular and bantam; both bearded and non-bearded
in both sizes * Rhode Island White, normal
and rose-comb


White chicken breeds with "recessive white"

*
Ameraucana The Ameraucana is an American breed of domestic chicken. It was developed in the United States in the 1970s, and derives from Araucana chickens brought from Chile. It was bred to retain the blue-egg gene but eliminate the lethal alleles of the p ...
, white; large fowl and bantam varietie

* Araucana chicken, Araucana, white
* Asil chicken, Asil, whit

* Australian Langshan (little-known outside Australia

* Australorp, white, regular
and bantam * Barnevelder, white, large/banta

(source in German) *
Bearded d'Uccle The or Belgian d'Uccle, , is a Belgian breed of bearded bantam chicken. It was first bred in the town of Uccle on the outskirts of Brussels, in central Belgium, in the early years of the twentieth century. It is a true bantam, with no stan ...
bantam, white * Catalana del Prat, ('white'

* Cornish chicken, Cornish white, regular
and bantam * Cochin chicken, Cochin white, regular
and Frizzle (chicken plumage), frizzle * Langshan, white
* Cubalaya, whi

* Dorking, white, rose-comb
* Faverolles chicken, Faverolles, white, regular
and bantam * Frizzle chicken (breed), Frizzle, white, regular and bantam (the term can also describe the frizzle plumage type as well as this specific breed) * German Langshan *
Japanese Bantam The Japanese Bantam or Chabo () is a Japanese breed of ornamental chicken. It is a true bantam breed, meaning that it has no large fowl counterpart. It characterised by very short legs – the result of hereditary chondrodystrophy – and a la ...
white *
Jersey Giant The Jersey Giant is an American breed of domestic chicken. It was created in Burlington County, New Jersey, in the late nineteenth century. It is among the heaviest of all chicken breeds.
* Lamona (practically
extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...


* Langshan bantam, white
* Malay chicken, Malay bantam, white * Old English Game, white, regular and bantam *
Orpington Orpington is a town in Greater London, England, within the London Borough of Bromley. It is 13.4 miles (21.6 km) south east of Charing Cross. On the south-eastern edge of the Greater London Built-up Area, it is south of St Mary Cray, sou ...
, white, regular
and bantam * Plymouth Rock chicken, Plymouth Rock, white; regular
bantam, and dwarf *
Silkie The Silkie, also known as the Silky or Chinese silk chicken, is a Chinese breed of chicken named for its atypically fluffy plumage, which is soft to the touch, like silk or fur. Other unusual qualities include black skin and bones, blue earlob ...
, white, non-bearded or bearded (recessive white); and bantam, white, non-bearded *
Sultan (chicken) The Sultan is a Turkish List of chicken breeds, breed of crested chicken. The name derives from the original Turkish language name of ''Sarai-Tavuk'', which translates as "fowls of the palace". They have always been primarily ornamental, having b ...
white * Transylvanian Naked-neck, white
regular and bantam * Wyandotte chicken, Wyandotte, white,
regular and bantam * Yokohama chicken, Yokohama, white


Solid white plumage in other species

The occurrence of solid white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
is widespread among avian species. Such
phenotypes In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological properti ...
result mostly from single
mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, ...
s associated with absence of
melanin Melanin (; ) is a family of biomolecules organized as oligomers or polymers, which among other functions provide the pigments of many organisms. Melanin pigments are produced in a specialized group of cells known as melanocytes. There are ...
deposition.


Turkeys (''Meleagris gallopavo'')

Original wild
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color of turkeys (''
Meleagris gallopavo The wild turkey (''Meleagris gallopavo'') is an upland game bird native to North America, one of two extant species of turkey and the heaviest member of the order Galliformes. It is the ancestor to the domestic turkey (''M. g. domesticus''), w ...
'') is bronzed, but solid white plumage color due to an autosomal recessive allele (''c'') in homocygosis is the most frequent phenotype, extended by domestication and imposed by the requirements of meat processing plants. Hutt and Mueller (1942) found a partial albinism in bronzed turkeys determined by a simple sex-linked gene, which is semi-lethal during incubation period or later. The blindness associated with this albinism limits the individuals to find water and food. Incomplete sex-linked albinism in turkeys in different from that of chickens. The mutation in turkeys eliminates
melanin Melanin (; ) is a family of biomolecules organized as oligomers or polymers, which among other functions provide the pigments of many organisms. Melanin pigments are produced in a specialized group of cells known as melanocytes. There are ...
from the retina, causing blindness and resulting lethal to most individuals.


Japanese quail (''Coturnix japonica'')

There is solid white feathered variety of Japanese quails ('' Coturnix japonica'') with dark eyes. Solid white feather is due to an autosomal recessive allele (''wh'') in homocygosis, although some birds may exhibit a few black spots. This mutant color gene produces a white quail with dark eyes when homozygous and two-color pattern known as "tuxedo" when heterozygous. The tuxedo pattern is white on the ventral surface, including the neck and face, while the dorsal surface is an intermingling of black and brown pigment. There is also another mutation (''W'') which is autosomal incomplete dominant. Homozygotes for this
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color mutant have white
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
, whereas heterozygotes for the gene show a diluted
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
color. But quails homozygous for this gene have low viability. It has also been described an imperfect sex-linked albinism due to the recessive allele ''al''. This pigmentation mutant results in subnormal levels of pigmentation of the eyes and feathers of affected quails. Faint stripes on the backs of the adults is apparently due to structural color only. Perinatal viability is reduced in quails homozygous for this gene.


Wild canary (''Serinus canaria'')

There is a semi-albinism in the wild canary (''Serinus canaria'', ''Fringillidae'') which produces pink eyes at hatch. Eyes darken in the adult phase and the
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
is not solid white but described as cinnamon. This is due to a sex-linked gen and was the first experimental demonstration of sex-linked inheritance in birds after the rediscovery of Mendelian laws. An autosomal dominant white has been also described in the wild canary which is lethal in homozygosis. All individuals studied happen to be heterozygotes, giving a progeny of white and colored birds in a proportion of 2:1. Homozygotes die in an early phase of embryonic development.


Other avian species

Kokemüller (1935) described a sex-linked albinism in the
budgerigar The budgerigar ( ; ''Melopsittacus undulatus''), also known as the common parakeet, shell parakeet or budgie ( ), is a small, long-tailed, seed-eating parrot native to Australia. Naturally the species is green and yellow with black, scallop ...
(''Melopsittacus undulatus'', ''Psittacidae''). This kind of albinism eliminates
melanin Melanin (; ) is a family of biomolecules organized as oligomers or polymers, which among other functions provide the pigments of many organisms. Melanin pigments are produced in a specialized group of cells known as melanocytes. There are ...
and the structural color found in the gene carriers, leaving untouched lipochrome pigments. As a result, budgerigars, which otherwise would be green with a few black spot, become brilliant yellow with pink eyes. Cook (1939) described an hereditary albinism in the
American robin The American robin (''Turdus migratorius'') is a migratory bird of the true thrush genus and Turdidae, the wider thrush family. It is named after the European robin because of its reddish-orange breast, though the two species are not clos ...
(''Turdus migratorius'' L., ''Turdidae''). McIlhenny(1940)McIlhenny, E.A. 1940 Albinism in mockingbirds. ''Journal of Heredity''. 31, 433-438. found a type of albinism in the
northern mockingbird The northern mockingbird (''Mimus polyglottos'') is a mockingbird commonly found in North America, of the family Mimidae. The species is also found in some parts of the Caribbean, as well as on the Hawaiian Islands. It is typically a permanent B ...
(''Mimus polyglottos'' L., ''Mimidae'') which is inherited as a simple autosomal recessive.


See also

* Lavender (chicken plumage) * Solid black (chicken plumage) *
List of chicken breeds There are hundreds of chicken breeds in existence. Domesticated for thousands of years, distinguishable breeds of chicken have been present since the combined factors of geographical isolation and Selective breeding, selection for desired charact ...
*
List of chicken colours Breeders and fanciers of chickens accurately describe the colours and patterns of the feathers of chicken breeds and varieties. This is a list of the terms used in this context. Self Self-coloured chickens are those which display one solid ...


References

{{Reflist Chicken plumage patterns Bird colours