Dirty bottom syndrome
There are a variety of reasons why rabbits may suffer with a dirty bottom, either with feces or urine, both of which are potential attractions for flies, especially in warmer months of the year when flystrike is a common occurrence. Having urine or feces around their bottom can also cause the skin to become sore, inflamed and infected, so it is important to understand why the rabbit is affected and what can be done to resolve the problem.
A poor diet may be the single, most common cause of dirty bottom in rabbits