My mom called me asking to get some information for her. She has 4 year old rabbit that recently is having very soft stools that are super stinky. Also her urine is extreme strong. She can clean the cage and just after one pee or poop the smell is strong enough to be changed again. She is using the same litter as always and the smell has only occured recently. Also there has been no change in the buny's diet. Any advice?