Spatchcocked :

1. A method of preparing small fowl which involves removing the backbone so that the bird may be spread open and flattened for cooking.
2. As a verb, to prepare a small fowl as in 1, above.
3. As an adjective, describing a fowl which has been prepared according to 1, above, as in “spatchcocked”.
4. Although not found in any dictionaries to date, “spatchcock” is in common use as a noun meaning a small spring chicken, usually no older than 6 weeks.

Spatchcocking is considered by many to be the equivalent of butterflying. However, some make the distinction that butterflying is more correctly defined to be making a single cut in a boneless piece of meat, poultry, fish or vegetable. Spatchcocking, on the other hand, is applied only to whole poultry.

It is conjectured that the term spatchcock, which was popular in 18th century cooking, derives from the saying “dispatch the cock.” By splitting and flattening a small fowl it cooks faster and hence the process is speeded up or dispatched for cooks in a hurry.

The term is related to spicthcock which refers to a similar method for preparing eel.

For a more detailed investigation into the etymology of the word spatchcock follow this link to the nakedwhiz.com