Uh I have a big water bottle on the side of Nebo's crate and I've never had a problem. All it took was a dab of peanut butter on the end for Nebo to figure out water comes out when he licks it. And yes he drinks out of a bowl all other times, but he'd just flip a bowl of water if I left it in his crate with him. He's a dog of course but I don't see why it couldn't work for a rabbit.