Twenty-nine varieties of chicken (and one Guinea Fowl).
There are hundreds of chickenbreeds in existence.Domesticated for thousands of years, distinguishable breeds of chicken have been present since the combined factors of geographical isolation and selection for desired characteristics created regional types with distinct physical and behavioral traits passed on to their offspring.
The physical traits used to distinguish chicken breeds are size, plumage color, comb type, skin color, number of toes, amount of feathering, egg color, and place of origin. They are also roughly divided by primary use, whether for eggs, meat, or ornamental purposes, and with some considered to be dual-purpose.
In the 21st century, chickens are frequently bred according to predetermined breed standards set down by governing organizations. The first of such standards was the British Poultry Standard, which is still in publication today. Other standards include the Standard of Perfection, the Australian Poultry Standard, and the standard of the American Bantam Association, which deals exclusively with bantam fowl. Only some of the known breeds are included in these publications, and only those breeds are eligible to be shown competitively. There are additionally a few hybrid strains which are common in the poultry world, especially in large poultry farms. These types are first generation crosses of true breeds. Hybrids do not reliably pass on their features to their offspring, but are highly valued for their producing abilities.
All chickens lay eggs, have edible meat, and possess a unique appearance. However, distinct breeds are the result of selective breeding to emphasize certain traits. Any breed may technically be used for general agricultural purposes, and all breeds are shown to some degree. But each chicken breed is known for a primary use.
Many breeds were selected and are used primarily for producing eggs, these are mostly light-weight birds whose hens do not go broody often.
The generalist breeds used in barnyards the world over are adaptable utility birds good at producing both meat and eggs. Though some may be slightly better for one of these purposes, they are usually called dual-purpose breeds.
Since the 19th century, poultry fancy, the breeding and competitive exhibition of poultry as a hobby, has grown to be a huge influence on chicken breeds. Many breeds have always been kept for ornamental purposes, and others have been shifted from their original use to become first and foremost exhibition fowl, even if they may retain some inherent utility. Since the sport of cockfighting has been outlawed in the developed world, most breeds first developed for this purpose, called game fowl, are now seen principally in the show ring rather than the cock pit as fighting cocks.
U denotes a breed primarily used for exhibition, but which is still used for utility purposes.
Most large chicken breeds have a bantam counterpart, sometimes referred to as a miniature. Miniatures are usually one-fifth to one-quarter the size of the standard breed, but they are expected to exhibit all of the standard breed's characteristics. A true bantam has no large counterpart, and is naturally small. The true bantams include:
Many common strains of cross-bred chickens exist, but none breed true or are recognized by poultry breed standards. Thus, though they are extremely common in flocks focusing on high productivity, cross-breeds do not technically meet the definition of a breed. Most cross-breed strains are sex linked, allowing for easy chick sexing.