I'm so worried about my rabbit. He has had this problem for a long time. I wash him and try to cut it off, but it's such a hassle. He runs,grunts, and tries to bite me. I'm worried I'm hurting him, but idk what else to do. He cant sit and holds his butt up. I thought I got it all off but maybe not. I live at home and nobody will take him to the vet. I really dont want him to die. Just let me know if it's something I should be worried about. He never has eaten his Timothy hay too often, but he also never had this problem before. I heard it could be diet related but I give him everything he should have.