My chin used to be an awful bather. I was using blue sparkle, so when I got his bath house, it came with that super pet sand, which as well all know isnt that great. So I put it in there, and mixed blue sparkle with it, at that point desperate to try anything. I think the coarser sand sparked his intrest, and all the sudden after mixing the two together, he bathes like a madman. Its like a whole new chin, he used to just kick a little bit of sand under his stomach and hop out, now he stays in there and i have a hard time getting him out! try something like that, maybe itll work. I dont know if the ones that arent taking a bath are with other chins, but if not, maybe try taking all the other chins out of the cage, and just one at a time, see if they will bathe that way, all by themselves. I feel your pain on this one, I had a horrible time with my chin, his fur used to look awful! good luck!