Early in John Updike's first novel, The Poorhouose Fair, from 1958, set in an old people's home, one of the outspoken residents says: "Is he [the head administrator], putting tags on us se we can be trucked off to the slaughterhouse?" so, there's Updike, Vonnegut, Coetzee , TRP (in Against the Day) and others, I'm sure.