A diet high in fiber is key. Any type of grass hay will do, and there are pellets with a high fiber content (Oxbow, Supreme Science Select, Fibafirst.) When bunnies get sticky poop, it’s most often because they get too many pellets or too many treats or some type of veg that they don’t tolerate. Cutting out all sweet treats should be the first action to take. Carrot actually counts as a treat – it’s high in sugar.
Bunnies are supposed to eat the type of poop that easily can become mushy and stick to their bottom. They’re supposed to eat it directly as it comes out. If they don’t, they don’t want it later on. Rabbit vet Richard Saunders say they don’t actually like the taste (exactly how he knows this, I don’t know. But it could explain why bunnies are so reluctant to clean their own poopy butt.)
There are a few different reasons why a bun won’t eat the cecals when they come out. They can be fat so they can’t reach. They can be old and arthritic so they can’t reach. They can have difficulty getting the signal that the cecal is on its way out (that’s also often en effect of aging – signals from the bottom to the brain doesn’t come through as they should).
You can give a bunny a butt bath with lukewarm water if the butt is really dirty. Just make sure you pat the bunny dry after. Cautious blow-drying is appreciated by some buns (hold one hand near the bunny butt so you immediately can feel if it gets too hot). If your buns get poop on their tummies, they might be over-weight. If the bunnies butts aren’t extremely dirty you can give a dry bath by rubbing in some corn starch and then brushing or combing it out.
Leafy greens are often fiber-rich and healthy but some buns react to some greens. Dandelion is generally tolerated. Fennel tops and dill and mint are traditionally used for tummy trouble.