In the USA, a Cornish game hen, also sometimes called a Cornish hen, poussin

Poussin (chicken)

In Commonwealth countries, poussin is a butcher's term for a young chicken, less than 28 days old at slaughter and usually weighing 400-450 grammes but not above 750g...

, Rock Cornish hen, or simply Rock Cornish, is a hybrid chicken

Chicken

The chicken is a domesticated fowl, a subspecies of the Red Junglefowl. As one of the most common and widespread domestic animals, and with a population of more than 24 billion in 2003, there are more chickens in the world than any other species of bird...

 sold whole. Despite the name, it is not a game bird, but actually a type of domestic chicken. Though the bird is called a "hen", it can be either male or female. In addition to commanding a higher price, the game hens have a shorter growing span, 28 to 30 days as opposed to 42 or more for regular chicken.

The U.S. Department of Agriculture describes the Rock Cornish game hen or Cornish game hen as "a young immature chicken (less than 5 weeks of age), weighing not more than 2 pounds ready-to-cook weight, which was prepared from a Cornish chicken or the progeny of a Cornish chicken crossed with another breed of chicken."

The Rock Cornish game hen or Rock Cornish hen is a cross between the Cornish Game and Plymouth or White Rock chicken breeds. This breed develops a large breast over a short period of time compared to game hens. Rock Cornish game hens weigh about 2.5 pounds after four to six weeks, at which time they're slaughtered.

Most sources credit Alphonsine "Therese" and Jacques Makowsky of Connecticut

Connecticut

Connecticut is a state in the New England region of the northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, and the state of New York to the west and the south .Connecticut is named for the Connecticut River, the major U.S. river that approximately...

 for developing the small bird in the mid-1950s. A Saturday Evening Post article from July 1955 credited Mrs. Makowsky with coming up with the idea to breed the Cornish game chicken, a small bird with short legs and a plump, round breast that she had discovered in a book. The Makowskys began cross-breeding the Cornish

Cornish (chicken)

The Cornish, known as the Indian Game in its native country of Cornwall in England, United Kingdom, is a breed of chicken. Cornish chickens, as well as crosses of Cornishes, are the most-used breed in the chicken meat industry...

 game cocks with various chickens and game birds, including a White Plymouth Rock Hen and a Malayan fighting cock, to develop the Rock Cornish game hen, a succulent bird with all-white meat suitable for a single serving.

External links

http://www.wattagnet.com/146546.html
http://www.usda.gov/wps/portal/usda/usdahome?q=cornish+game+hen&navid=SEARCH&Go_button.x=21&Go_button.y=11&site=usda&x=20&y=13

• USDA Standards and Grades for Poultry
• Cooking Information and Recipes
• Te Makowsky -- original breeder of the Rock Cornish game hen, San Francisco Chronicle, December 1, 2005