Any ideas to get litter training back from the dead? Dusty and Willow have stopped using it and making a huge mess of their big hutch. They've been littertrained in hutch for 1.5 yrs. Started getting wee in one different corner of hutch, moved tray accordingly and wherever I move tray to they wee elsewhere! They must think it's a game! They win! Got annoying and messy now! Any similar experiences or solutions? Thanks!