Prohibiting the routine use of antibiotics in farm animals, necessary to slow the evolution of resistance genes that can spread to organisms that cause disease, has led to a new form of drug smuggling.

I don't think this will be as hard to control as smuggling addictive drugs. A farm uses the antibiotics to increase its profits, so it won't pay any more than the increased profit would be. Indeed, given the risk of legal trouble, it won't pay even half that much.