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This is the first part, certainly the most important to understand and find out about the origins and history of today's existing breeds … including the ones populating your own hen house. We therefore advise you to read it carefully. At the bottom of the page you will find a section dedicated to the Italian breeds and one dedicated to the foreign ones. Should you want to find out more about the origins, history and evolution of chickens, please visit the web site Summa Gallicana, where Dr. Corti's exhaustive researches will satisfy your curiosity under each and every aspect.

The Hen House's Staff

The Gallus Gallus, Wild Ancestor of Domestic Chickens

The wild varieties of domestic chickens can be classified in four species:
· Gallus gallus Linnaeus
· Gallus sonnerati Temminck
· Gallus lafayetti Lesson
· Gallus varius Shaw

Gallus gallus Linnaeus
The Gallus Gallus species includes five local subspecies:
Gallus gallus gallus Linnaeus
Male: head and hackle, dark orange or orange red coloured, turning orange and deep yellow on the tips of the longest neck feathers; rump feathers beneath the neck hackles and lower wing coverts are black with a green or purple blue sheen; scapulars, middle wing coverts and back are dark brown red, turning into deep orange on the long sharp saddle hackles and the lesser upper rectrices or tail coverts; secondaries and primary coverts displaying a blue and green sheen; the remiges are black, with a brown external edging in the primaries, while the external half of the vane (i.e., the barbs considered collectively as a flat surface) is chestnut or brown red; abdomen and lower part of the body black with green sheen; main upper tail coverts and tail, black with green and purple blue sheen. Beak dark brown; comb and wattles red, white earlobes, other non-feathered parts on the head and neck, red; slate grey shanks.
During the summer moult, the black and tan striped hackles and lanceolates or neck hackles are replaced by regularly shaped, hen-like feathers, of a soot black colour. The hackles grow again in the autumn.
Hen: The hen's head and neck hackles are yellow, the latter also showing black flames in the length. The back and shoulders are of a uniform brownish colour; every feather is black-pencilled, with a neat, deep golden lacing. The rachis or shaft is whitish yellow. The primaries are slate brown, the outer barbs showing a thin brown edging/brim. The secondary wing coverts or remiges are brown, with finely pencilled light brown barbs.
The breast is a light salmon colour; shanks and abdomen, ash brown with finely edged feathers. The tail is black and brown pencilled (Ghigi A., 1968; Giavarini I., 1983).
This subspecies inhabits the forest areas of Cambodia, Cochinchina and Annam. Its main characteristics are the white earlobes, and the very long neck and saddle hackles.

Gallus gallus gallus Linneo

Gallus gallus murghi Robinson & Kloss
In its outward aspect, this subspecies is very similar to the previous one: it displays white, slightly smaller earlobes, very sharp neck and saddle hackles of a very deep yellow, the longest of which tend to turn gold and have a rather wide black stripe in the middle. The hen does not differ significantly from the previously described, except for the smaller earlobes.
This subspecies is native of North East India and Himalaya (Ghigi A., 1968; Giavarini I., 1983).

Three pictures of a specimen of Gallus gallus murghi Robinson & Kloss

Gallus gallus spadiceus Bonnaterre
This subspecies does not sensibly vary as far as plumage is concerned. Its lanceolates are in the average shorter than the gallus' and its earlobes are small and red. Apart from this, it displays no differences to the nominal subspecies.
It is native of South West Yunnan, Burma, Siam, with the exception of North East Laos, the Malacca peninsula and the area North of Sumatra (Ghigi A., 1968; Giavarini I., 1983).

Gallus gallus spadiceus Bonnaterre

Gallus gallus jabouillei Delacour and Kinnear
This subspecies has smaller comb and wattles compared to the other ones; also, earlobes are red and small. The plumage's red is darker, the neck hackles are shorter and less sharp; the saddle is mahogany red, while the hackles are small and dark red; the tail is slightly shorter, the neck - very dark - is tinged with orange.
It is native of Tonkin, South East Yunnan (China) and Northern Annam (Ghigi A., 1968; Giavarini I., 1983).

	Gallus g. jabouillei Delacour e Kinnear in eclisse		Gallus g. jabouillei Delacour e Kinnear

Gallus gallus bankiva Temminck (Gallus gallus ferrugineus Gmelin)
Very similar to the Spadiceus subspecies, it is just distinguishable by the neck hackles, that are rather wide and round-edged, a unique characteristic among all subspecies. Earlobes are red with white irregular stripes, the shanks are slate blue. When mentioning the wild Gallus species, ancestor of the domestic one, the denomination in use has always been bankiva, perhaps because the native populations kept taking specimens of this species when travelling to the Eastern islands; these specimens adapted rapidly to their new environment.
Originally, this subspecies - also known as red jungle fowl - inhabited the South of Sumatra and the islands of Java and Bali. It is likely to have been introduced, however, in the Philippines, Tahiti and as far as Hawaii, where the local population donated a specimen as a present to Captain Cook (Ghigi A., 1968; Giavarini I., 1983).

Gallus gallus bankiva Temminck (Gallus gallus ferrugineus Gmelin) Photos courtesy of Feathersite.com

Gallus sonnerati Temminck
The Sonnerat fowl, called after the scientist who discovered it, is also known as grey jungle fowl, lives preferably in mountain areas, sometimes as high as 1,500 - 2,000 metres. As opposed to the other subspecies, the Sonnerati can easily fly. Its main characteristic is the extraordinary dilation of the apical part of the shaft, or rachis in the neck and saddle hackles, and the tail coverts. Through this dilation, these feathers seem covered with scales, which confers them a very different look. During the summer moult, the neck hackles are replaced by short feathers with a regular structure.
Cock: The feathers on the head, neck and forepart of the rump are black, with grey fringes, a white bar and a straw-yellow stain in the terminal part; the remaining part of the saddle and rump, including the marginal wing coverts are purple shaded, with a grey edging and a thin white stripe along the shaft; the main saddle feathers display orange and red fringes and are embellished with yellow flame-shaped spots in the apex; the middle wing coverts and the scapulars are black, with a white yellowish stripe along the shaft that expands towards the apex in a wide orange spot with external red fringes.
Primaries and primary coverts, brown-black. Abdomen, lower parts of the body and keel grey, with side hackles displaying reddish fringes in their apex. Tail, black with green sheen. The comb is small, with a very slight indentation, red earlobes, horn-coloured beak, deep orange yellow shanks.
Hen: All neck and rump feathers display white yellowish stripes along the shaft; the outer vanes of the secondaries are finely stained with soot brown and black; the breast feathers have visible black and white stripes. The comb is extremely small, the head presents a very limited non-feathered area.
It inhabits Western, Centyral and Southern India (Ghigi A., 1968; Giavarini I., 1983).

some specimens of Gallus sonnerati Temminck Photos courtesy of Feathersite.com

Gallus lafayetti Lesson (Gallus stanley Gray)
Cock: Orange reddish head, golden plumage with black stripes in the length. Chin and throat feathers form some sort of cravat differing in color from the breast's red. Rump, red with black stripes; saddle feathers purple red at the base, with a blueish hue at their apex. Wing coverts, orange red with central black stripes. Primaries, blackish brown; secondary wing coverts with blue sheen; tail black, also with blue sheen. Abdomen, bright red with fine black stripes. Comb, rhomboidal-shaped with indentation, higher on the back, with a visible, diagonal yellow stripe in contrast with the remaining red parts. Beak, brown; shanks, yellow red; iris, yellowish white. As opposed to the previously described species, does not undergo any periodical hackle moult.
Hen: It differs from the G. gallus hen for its neck and saddle hackle fringes being less wide and a darker red. The secondary wing coverts are black, with brown yellowish stripes in the width; breast and side feathers are black with leather red speckles and whitish stripes in the length. The breast and the remaining lower parts are white, with irregular stripes and black edgings. The tail feathers are black, richly speckled with reddish brown. Extremely small comb, with coarse wattles, cheeks covered with feathers and a reddish eye contour/brim.
This subspecies inhabits exclusively the island of Ceylon (Sri Lanka), both in plane and mountain areas, where it can be found up to 1,700 mt. The male displays also an intermediate, juvenile plumage, brown buff in color, which differs from the adult's.
Gallus lafayetti Lesson (Gallus stanley Gray)

Gallus Lafayetti Lesson (Gallus stanley Gray)

Gallus varius Shaw (Gallus furcatus Temminck)
Cock: Head, neck and upper rump covered with rather short, abruptly ending feathers, black at the basis/quill, with a shade, blue in the centre and golden green on the remaining surface. Lower part of the rump, golden green with blue sheen, gradually turning into a purple shaded brass at the outer ends. Saddle and tail covert hackles, black with golden yellow thin edging. Lower and middle wing coverts, long in shape, red orange in color with a long central black stripe; primaries and primary coverts, black with a slight greenish blue shade. Abdomen and tail, black, also with a light greenish blue shade. The head sides and temples are featherless, scarlet in color; comb, rather developed, without indentation, green at the base and centre, turning purple red towards the outer parts; wattle uneven, placed centrally on the throat, scarlet, green and yellowish. Horn-coloured beak, flesh-coloured shanks, fire-red iris. It does not undergo any seasonal molt in the neck's feathers.
Hen: Head, neck and upper plumage parts are soot brown, with black subterminal/near the end and dark central stripes; the remaining upper parts, secondaries and secondary wing coverts are black, with soot black shadings and irregular yellowish stripes at the end; primaries and primary wing coverts, dark brown; cheeks, superciliary (eye brows) lines and face sides, light brown. Chin and throat, white; abdomen, leather coloured; breast feathers with brownish edgings, waist blackish speckled; tail, black with irregular brown stains/spots/speckles. The hen's comb and wattles are scarcely developed. This species is originary of Java, but is rather common also on the nearby islands of Madoura, Kangean, Lombok and Flores (Ghigi A., 1968; Giavarini I., 1983).

some specimens of Gallus varius Shaw (Gallus furcatus Temminck)

The Domestication of the Species (Gallus gallus)

Chickens in the Old Age

It could be worth reviewing what the Latin authors wrote about poultry farming in Roman times. Cato, who lived 234 - 149 b.C., reports very limited information about the raising of geese, pigeons and hens for consumption, and avoids the subject of breeding altogether. The treatises by Palladius, who probably lived in the Fourth Century of the Christian era and is therefore the last one of the Roman authors dealing with poultry farming, report but a few hints about the breeding of chickens by the hand of housewifes.
The oldest treatise writer after Cato is Varro (116 - 27 b.C), who leaves important subjects that were later resumed by Columella, the author of the first, actual complete treatise on poultry farming. Columella recommends selecting chickens with white ear lobes as being certainly more prolific than others, and to favour five-toed hens, thus corroborating the theory by certain English researchers, that the Dorking was a Roman breed, originally imported to Great Britain by Julius Caesar. Apart from the afore mentioned, chickens from Media, an ancient country in Western Asia (present day north-western part of Iran, Kurdistan, Azerbaijan and parts of Kermanshan) and Rhodes are vaguely reported as more beautiful and larger than the Romans', while the rich Roman families are said to have hosted cock fights on a regular basis.
It is a fact that every ancient population left documents mentioning the existence of wild chicken fowls that often were the favourite dish at Roman banquets. If on the one hand chickens are an every day appearance on the table all over the world, it is also true, on the other, that they were object of worship by several populations. Charles Darwin, when researching the origins of domestic species, concluded that domestic chickens could not have been originated by a primitive form which got extinct as time went by.
He based his theory also on the fact that the wild fowls belonging to the Gallus species were still preserved throughout the centuries. In his work On the origins of the species by means of natural selection he states: "Mr. Blyth, whose opinion, from his large and varied stores of knowledge, I should value more than that of almost any one, thinks that all the breeds of poultry have proceeded from the common wild Indian fowl (Gallus bankiva)" (he present classification/taxonomy classifies the bankiva as the Javanese subspecies, while the Gallus murghi reperesents the Indian one). Mr. La Perre de Roo rejects Darwin's theory: "there is no example whatsoever of any farm chicken returning to the wild".
The theories according to which human beings descend from apes, dogs from wolves, domestic pigeons from rock doves and finally domestic chickens from the bankiva fowl are all contemporary. Ancient Latin authors like Columella, Varro, Palladius who wrote about poultry animals two thousand years ago are even closer than us to the era of chicken domestication, and therefore certainly not less able than we are to research this subject. These authors report wild chickens to be rare birds, unable to reproduce in captivity, the only use of which was consumption; in fact, none of those eminent learned persons ever imagined wild species to be the ancestors of those domestic birds, several sorts of which were already domesticated.
With convincing arguments, Darwin states domestic chickens to have been originated by a single specific species, as "the bankiva cry is not very different from the game cock's". Spectrogram studies carried out in 1967 on the cry of Gallus gallus, Gallus sonnerati and Gallus Lafayettei made clear that the domestic species cry only resembles the Gallus gallus'. There were, though, important scientists rejecting Darwin's theory, such as Edward Brown, Lewis Wright and especially Tegetmeier, who took part with Darwin himself in several studies. In spite of this, he dared opposing Darwin's theory by saying that with all respect for the opinions of his eminent Master Darwin, he was induced to conclude by 'an accurate and exhaustive analysis of facts' that an Asian heterosomic chicken breed like the Cochin, i.e. differing in its somatic traits from the Gallus type, does not have the same common ancestor as a game cock. It is on the other hand still unclear how come that Darwin rightly observed the difference in morphology between the bankiva's and the Cochin's occipital openings, but did not change his monophyletic view on the common origin of the two breeds, due to the fact that there are no other ancestors of modern chickens other than the bankiva species.
Observing the Cochin's preference for staying on the ground, Darwin was nearly tempted to admit the possibility of a different ancestor for the two breeds (the large Asiatic breeds being supposed to have originated from an insular environment), but he resolved soon enough to draw a final conclusion based on the fertility of their hybrids. This was the occasion of further discussions about the possible crossing between wild and domestic fowls, until the issue was but partially resolved by Professor Ghigi's studies (1915). The latter was firmly convinced that domestic chicken breeds had originated not from one but from the several Asiatic wild species.
Some very recent archeological discoveries made in China prove chickens to have been introduced about 6,000 b.C. thanks to the previous domestication of the Gallus gallus which had taken place in South-East Asia, which view was also expressed by Charles Darwin. From China, via Korea chickens reached Japan in the Yayoi period (300 b.C-300 A.D). According to Barbara West and Ben-Xiong-Zhou, the oldest findings are as old as 6,000 b.C and come from the Chinese regions of Cishan and Peligan. This chronology precedes by 4,000 years the findings in Mehenjo-Daro, but not only that: the remnants from 16 out of 18 Chinese archeological sites precede the Indian ones. It is not clear whether the specimens bred in China contributed to the selection of the present domestic chicken. The latter's worldwide diffusion could be mainly due to the breeding by the Harrappa civilization in the Indus valley (2500-2100 a.C.). Some more studies also confirm that chickens were introduced to South America before the Sixteenth Century from Polinesia (Ghigi A., 1968; various authors, 1996).
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Traditional Chicken Breeding and Raising

Since the Latin authors, several centuries went by without any new contribution being added to the studies on domestic birds. The first to deal with the subject is Ulisse Aldrovandi, about whose works Charles Darwin wrote: that his Ornithology is the most complete document we can rely on to determine the age of our domestic chicken and pigeon breeds. One should not believe Aldrovandi to have not undergone some major errors, like for instance considering turkeys to be native of India and being introduced via Turkey, in line with the tradition by which Cristoforo Colombo on landing in the Antilles believed to have reached India. After the Sixteenth Century, poultry keeping started spreading together with the general development of rural activities carried out in most provinces by the farming class. This limitation to the range of activities of the rural class turned even more extreme when poultry keeping became the exclusive task of housewives and was held in low esteem by men within the farming people themselves. Within the sharefarming system, the raising of chickens was the peasant's task, the number of specimens and species to be bred being limited by the land owner. This limitation in the number of specimens, superimposed by means of written specifications of the farmer's duties, was usually violated by peasants who "illegally" bred a larger number of fowls, which violation became often the reason of altercations and controversies. Generally speaking, the farmers' agreements demanded a number of fowls for every category to be delivered to the land owner, and more specifically cockerels in August, capons for Christmas, hens for the Carnival parties and eggs at Easter. When the first international poultry exhibition was held in Paris, the general interest for this activity began to increase, especially for the most productive breeds. Thus was founded in the city of Modena an association for the improvement of poultry species that imported selected breeding stock from France and entrusted some enthusiastic farmers with the breeding. Declaring that the poultry farming industry needed improvement, in 1889 the most important Italian newspaper organized a national exhibition, followed by an international one a year later which was sponsored by the Lombardy press Association. That was the beginning of a rather substantial wave of interest in the techniques of poultry farming, with numerous exhibitions in Florence, Rome, Piedmont, and saw its climax in the international Milan exhibition of 1906, organized to celebrate the opening of the Sempione neck in the Alps. In the mean time, the Italian Poultry Association was born in Genoa, chairman of which became Marquis Gerolamo Trevisani, the author of several treatises on the subject. Following the proposal by the agricultural congress, in 1909 the government decided to create the so-called 'experimental poultry farming stations' with the task of acquiring further expertise on this crucial sector of animal husbandry. Due to the beginning of World War I, Italy not only saw a halt but also a drawback of its agricultural production. It was only on June 28th, 1917 that the crisis began to clear with the Department of Agriculture instituting by decree the Stazione Sperimentale di Pollicoltura (experimental poultry farming station) in Rovigo, which was to have a very significant part in the further development of the industry.

Industrial Poultry Farming

Already in 1892, well before Shull formulated his theory on heterosis, Cushman had noticed and stressed the fact that the first generation hybrids of two different breeds are more vigorous and easier to raise. Quite some time later, Warren resumed the subject and proved crossing products between white Leghorn and black Jersey Giants were superior to the parental breeds as far as productive characteristics are concerned. In spite of this, until early 1950 research and studies kept focusing on pure breeds, with positive effects on the general appearance and development, but contradictory results as far as other characteristics were concerned, as for instance the laying ability. One can safely state, therefore, geneticists in the poultry sector to have been the first one to reject the so far unquestioned superiority of pure breeds. With the arrival of intensive agriculture, ideas and experiences were no longer confined to labs but began to be put in practice by means of on-site testing. Improving laying ability with traditional methods, such as mass selection by means of the progeny test and strain selection, turned out to be increasingly difficult. For chickens raised for meat consumption, researches focused on methods and techniques that would allow the industry to remain competitive in an expanding market. In this contest, breed crossing was increasingly applied as being the only reproductive system that allows taking advantage of a whole series of previously neglected genetic effects, such as dominance, superdominance and epistasis. The U. S. Agricultural Research Service reports that as early as 1955-56 43% of the chicks bred in the United States was the result of breed crossing. At present, all chickens bred for commercial purposes worldwide are hybrids. Pure breeds have ceased to be used for production purposes. All commercial cross-breeds in the laying industry were obtained with two methods: hybridization of in-bred lines and strains crossing, often in its more advanced version, i.e. recurring reciprocal selection. Around 1975, the hybridization of in-bred lines and recurring reciprocal selection were abandoned in favour of strain crossing, a less complex and expensive technique which allowed more flexibility within the market fluctuations.
It is curious that several of the modern highly productive strains - for laying hen as well as for chick destined to meat consumption - come from a restricted number of selectors, i.e. no more than 6 or 7, while some of these strains may even have a common origin. Today's worldwide distribution turns out to have, therefore, a surprisingly restricted genetic basis. This implies risks that need to be evaluated, as well as stresses the necessity to preserve and defend the genetic asset represented by the still existing pure breeds and varieties. Several are the researchers who believe an annual production of 230 to 260 eggs to be a threshold modern genetics can hardly hope to improve. This is not due to some running out of genetic variety, but to the negative effect of the genetic interweaving between the different characteristics that are being pursued, as for instance the small size of the hen's body and the large dimension of its eggs on the one hand, and the laying figures on the other. The typical early Fifties broilers reached a weight of 1.2 - 1.3 kg at 12 weeks, with a production index of 3 to 3.4. The medium sized broilers in the Seventies reached 1.8 - 2 kg in 8 weeks, with conversion indexes often below 2.2 - 2.4. This improvement is still going on at present, and there is no evidence of any final phase to have been reached. The only risk in this pursuit of weight increase is that of decompensation in the animals' metabolism, with various negative effects. This is probably the main reason of the problems recently ascertained within hyper-heavy broiler strains (Giordani, G., 1975).

Mutations in Domestic Chicken Breeds

COMB

The comb is one of the characteristics most subject to vary and constitutes a reliable means in identifying the various breeds and varieties. Most wild species have a single, regularly indented comb, with the exception of the Gallus lafayetti and Gallus varius that display respectively a rhomboidal-shaped comb with fine indentation and a non-indented single comb.

Single comb: skin duplication, the upper edge of which has various points; the rear blade can vary in size and may or may not follow the line of the neck. Independently from the size, in cocks it is required to be carried perfectly straight; in hens, the comb is carried straight in certain breeds (Plymouth Rock) or folded on one side in others (Leghorn).
Cup comb: two fleshy blades, the upper edge of which have regular points closing together in the rear in the shape of a cup (Sicilian Buttercup).
Butterfly comb: two tissue blades carried wide apart from each other and ending in points. It is typical of crested breeds (Houdan).
Horn comb: a fleshy protuberance outgrowing in two finger-shaped appendixes that are carried straight upwards starting from the nostrils. Often to be observed in crested breeds (La Flèche).
Triple or pea comb: three lobes set length-wise and covered with small tubercles so as to resemble an open pea pod.
Mulberry comb: small, roundy mass finely covered with tubercles (Silkie).
Cushion comb: fleshy, relatively small mass adherent to the head and perfectly smooth.
Strawberry or Walnut comb: small fleshy mass, covered with more or less small tubercles, resembling a half strawberry or walnut.
Rose comb: compact and wide fleshy mass, covered with innumerable rounded tubercles. Wide in the front, it gets narrower in the rear to become a finger-shaped appendix called leader, that may rise or follow the round line of the neck (Hamburg, Wyandotte). (Giavarini I., 1983; Pozzi G., 1961; Brunoli A., 1971).
Blade comb: skin duplication the upper edge of which is smooth and the rear blade expanding in various degrees (to be found in certain production strain Leghorns).
Combless: tiny flesh mass above the nostrils.

		comb drawings from an old print

Ear-lobes and Wattles
Ear-lobes are a characteristic that helps in distinguishing Mediterranean from Asiatic breeds. Among the wild Gallus gallus species are also varieties with differently pigmented ear-lobes. A white ear-lobe is a typical feature of Mediterranean breeds and is developed in the highest degree in the Andalusian, where the pigmentation of the whole head is white, except for the comb and wattles. In heterosomic Asiatic breeds, the ear-lobe is invariably red, as well as in many American breeds of Asiatic descent. Certain breeds have blueish white ear-lobes.Wattles are generally well developed in cocks, except for certain game breeds which instead of those have an extremely developed throat fold / plait (Mazzon, I., 1928)

Crest, Mufflings and Beard
The crest can be round shaped and voluminous, or rather smaller in size, pyramid-shaped and carried erect. It can rest on an anatomic anomaly called cranial hernia, or originates from the nape like a mane. This mutation can occur together with an increased growth of the throat feathers - the beard - or of the cheeks', in which case it is called muffling. This characteristic can occur separately from the mutation of the crest. The increase in volume of beard and muffling causes the wattles to get smaller

Naked Neck
It can be a homozygotic or heterozygotic character; homozygotic specimens display a featherless neck the skin of which is red (Transylvanian Nudeneck). Heterozygotic ones, however, present the neck's lower front area covered with a feather cuiff, while the remaining part is naked (Forez Nudeneck).

Form, Texture and Length of Feathers
There are several mutations concerning feathers in chickens, some of which being the character upon new breeds were selected. There are breeds characterized by curly feathers, i.e. feathers growing in the opposite direction as the regular ones. Another common mutation is the silky plumage, where the barbs do not collate so that the feathers acquire a woolly appearance. The tail and hackle feathers in some Asiatic breeds undergo a continuous growth and do not molt (Phoenix, Yokohama).
For some reason, domestication seems to have suppressed the male's eclipse molt; this, although genetically dominant, does not occur in any domestic breed and tkes place exclusively in wild fowls of the gallus species.

		tail drawings from an old print

Mutations of The Limbs
Colour mutation: it is responsible for the existence of numerous colours, also reflecting the market's demands. In the past, in fact, consumers seem to have preferred chickens with blackish shanks, while at present commercially bred chickens must have yellow shanks. Also, white-pink, green, blueish and stained shanks are to be observed.
Fifth-toe mutation: soem of the in Europe most popular breeds present an additional toe (Dorking).
Booted-legs mutation: many heterosomic Asian breeds are endowed with more or less thickly booted shanks.
Short-shanks mutation: it is typical of certain breeds Courtes Pattes, Chabo).
Vulture-hock mutation: anatomic anomaly by which the animals present the posture of the vulture, in concomitance with an increased development of the thigh's feathers that causes them to be called breeches (Sabelpoot) (Pèriquet J. C., 1994; Giavarini I., 1983).

		different shank types from an old print

Lack of Coccydeal Vertebrae
A mutation that occurs in the South American breed Araucana and some rumpless breeds in Europe (Barbue d'Everberg).

Skin Color Mutation
The skin can be white or yellowish, depending also on the kind of nourishment. Ther are, though, breeds with an extremely dark skin and meat (Silkie). There seems also to be a mutation similar to the one occurring with guinea fowls, by which the connective subcutaneous tissue turns black-purple, which is particularly visible after cooking.

Iris Pigmentation
It is generally of a reddish color, but exceptions can be observed also among wild species (Gallus lafayetti, displaying a pearl-white iris). The standard of certain breed demands very dark or almost black eyes (Bresse, Campine).

Body Conformation and Dimensions
Concerning the shape, it may be interesting a classification proposed in 1905 by Ghigi, who groupes the various chicken breeds as follows:
- homosomatic breeds, that is to say, those which by form and spatial relationship of body parts most resemble the Gallus species. These lay white-shelled eggs, are precocious in their development and particularly good layers (Leghorn, Hamburg, Padua, Bresse, etc);
- heterosomic breeds, in which shape and correlation of body parts differ sensibly from those of the typical wild species that are considered to be the ancestors of our domestic one; the egg shell is red, are slow in the completion of plumage and sexual maturity (about 8 months), do not lay abundantly and are more apt for meat production (Brahma, Cochin).
- intermediate breeds, deriving from the crossing of the two afore mentioned types, with morphological and functional characteristics of both groups; they are good layers and produce quality meat. The most important ones have been created in America and are largely employed at present to obtain hybrids for commercial purposes (Plymouth Rock, Rhode Island, New Hampshire, Wyandotte).
There are also breed that do not fully fit into this classification, as game, bantam and fancy breeds, so called for their peculiar characteristics.
In the light of this classification, several were the theories formulated in the past on the origins of heterosomic breeds, including the hypothesis by which they would be island breeds, due to the lack of flying ability. Recent archaeologic discoveries, though, proved that chickens were introduced in China around 6,000 b.C. One may reasonably suppose that this domestication originated the heavy heterosomic chickens, while the homosomic ones could be fruit of a more recent attempt at domestication, which took place during the Roman age and spread widely in the rest of Europe.

Plumage
The number of different liveries which were obtained by selection is remarkable, and while some breeds identify themselves with one colour, numerous ones are recognized in others.
The livery sort was determined by several factors, such as commercial requirements, that at first demanded black liveries but in a second phase changed their preferences to white because - once plucked - the latter did not display unpleasant coloured follicles. This is the reason why nowadays the coloured livery strains tend to disappear.

Egg Colour
Egg shells can be white, as in Mediterranean breeds, brick-red like in the Asian ones, slightly pink or green. South European consumers preferring strongly pigmented egg shells, breeders were induced to select strains laying coloured eggs. (Cittadini, A., 1929). (see page on Eggs)

Feather Growing Ratio
Mediterranean breeds are characterised by rapid feather growth, a desirable quality in all breeds.

Hatching Instinct
Once the clocking instinct was no more of practical use, it has been eradicated by aimed selection. The Asiatic breeds still retain their tendency to clock, together with a number of bantam breeds, which are often used for hatching wild fowls'eggs.

	a clocking hen	eggs hatch 21 days later	a few hours old chick

Texts by Dr. Alessio Zanon, Ph.D.; Translation by Dr. Stefano Bergamo

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