My rabbit is about 8-9 years old and recently stopped using his litter box. I had to change brands of litter because the old one I was using changed to be too hard. I bought a bag of the rough stuff, thinking it would be fine. He hated it. I changed litter to another brand that's soft, he pees in it about once a day, leaving at least 2 separate accidents in his cage. He stopped pooping completely in his box, he just leaves huge messes next to his box, next to his food bowl. Do you think the change in litter turned him off, could it be old age, or something else? I tried moving his box, it doesn't work. This happened while I was typing this message up.