American Poultry Association
The American Poultry Association (APA) represents the portion of the chicken-raising community that produces birds for show and competitions. It is the APA that recognizes new chicken breeds, and establishes standards for those breeds. Their website contains a comprehensive list of every recognized chicken breed, as well as ducks and turkeys. The APA also maintains full information on the applicable standards for each breed, organizes and sanctions shows, and provides its members with useful information on avian diseases and their treatments.
My Pet Chicken
My Pet Chicken is a consumer-oriented site, aimed at those who wish to keep a few birds for pets, with eggs and entertainment value as side benefits. Their site contains the same list of breeds available from the APA, but augmented with photos of most breeds and other pertinent information, such as their egg color, egg-laying prowess and tolerance of cold. The site offers advice and useful information for the hobbyist on all aspects of rearing chickens.
Backyard Chickens
Backyard Chickens is another site aimed at the hobbyist, though the focus is less on chickens as pets and more on chickens for personal meat and eggs. Their list of breeds is formatted as a grid, evaluating and describing each breed based on a number of different criteria. These criteria include the breed's size, temperament, hardiness, broodiness and suitability to meat or egg production. For those wanting more than a few eggs but less than a full-scale farm, this site will provide most of the necessary information.
American Livestock Breeds Conservancy
One of the more interesting lists of chicken breeds is the one maintained by the American Livestock Breeds Conservancy. The Conservancy monitors the population of each chicken breed, and classes them according to their rareness and danger of extinction, just as other organizations do with wild animals. For many hobbyists, the knowledge that they are helping preserve a rare breed elevates the nurturing of their small flock with a personal sense of mission.