How is the hay-eating? Plentiful? Poop stuck to the fur is almost always diet related.
I would perhaps try dark leafy green veggies to substitute the broccoli, carrots and cauliflower. They can be a gas-producing, and any pain can slow the gut and result in messy/unformed cecotropes. Transition slowly of course. Herbs are great! Limit the pellets to a couple of tablespoons until the loose poops dry up. Make sure the pellets are timothy based, not alfalfa. Of course unlimited hay. If you know this stuff, my apologies for coming across as a know-it-all, I just wanted to cover the basics.
Some bunnies just have more sensitive stomachs than others, it sounds like Furby may be one of those. If the above doesn't work within a few days, it's time to see a vet for a overall physical, but specifically a dental exam with an otoscope (not just visual).