There could be many factors causing this – I’ve looked at your profile and your other posts but they really don’t tell enough about your rabbit – age, weight, diet, etc…to be helpful…can you give more information that might help answer your question.

Have you had him checked out by a vet – maybe the problem is a urinary tract infection or even dental problems can cause poopy butt and this is about the age that many rabbits start to have dental problems.

It’s typically a diet thing, either a new food that they don’t do well with, or too rich of a diet. It can also be a sign of dental issues. Some bunnies aren’t good at cleaning themselves down there and can get a little yucky.

Some rabbits are also just more prone to it than others. One of mine had awful poopy butt after getting a few mouthfuls of a different brand of pellets. My girl, on the other hand, has never had poopy butt no matter what she ate (and despite having dental problems when I got her)

My bunny Giuseppe had a bad case of poopy butt for the first time in his 10 year life a few months ago. Every day for 10 days, I would gently wash his privates with childrens shampoo and warm water, then blow dry. It is a two person job. Don’t try it alone especiall the first time. My wife helped me starting the second washing. After the first washing, his poopy butt got about 50% better. After about the first week, he was almost 100% better. Be very carefull — that first time, Guiseppe was so upset, he bit through my heavy sweatshirt and made my nipple bleed — the most paid ever experienced in my life! Oddly, after several washes he like the process and would melt in my arms during the blow drying. This might not be the best method, but it avoids the traumatic trip to the vet and is a natural cure. FYI — If I had not seen improvement by the second washing, STRAIGHT to the VET we would have gone. Giuseppe HATES the VET and trembles and urinates as soon as we put him in his carrier. Then his fur gets all wet with Urine and I get embarassed to have the Vet see him covered in his own urine.