It's a trick question, of course. I voted yes because you asked about owners, and therein you make an assumption. Owners can do what they like with their property, including drugging it. If we presume that people actually own other animals, then it follows that it should be legal. The better question would ask whether people can actually own another animals to begin with.
By that logic, bestiality with one's pets should be legal as well, no?
Atlas' Law: As a discussion goes on longer and longer the probability someone will mention bestiality approaches 1.
Poll
