Definition of "slunk"

Then I met a great guy, Placenta Juan the Afterbirth Tycoon. Made his in slunks during the war. (Slunks are underage calves trailing afterbirths and bacteria, generally in an unsanitary and unfit condition.)

1962 , William S. Burroughs, Naked Lunch, New York: Grove Press

Calf heads were tanned from yearling calves less than a year in age. Slunk skins were tanned from unborn calfskins which, gruesome as it sounds, were often by products of the cow slaughtering process.

2001, ed. Rob Cook, The Making of a Drum Company, Hal Leonard, published 2001, page 53