Ok - I would lay money on it being the burgess junior and dwarf that is causing it! I know and hear of soooo many bunnies who find burgess (the normal version) too rich and having these problems, including some of my own previously. The junior and dwarf is even richer than the normal one so it's bound to be worse.
How much of it is she having? Is she a youngster? I would suggest slowly cutting the amount down (how much does she have daily?) and swapping her over onto a different food such as science selective, which more often than not seems to resolve this! If she's a youngster, ideally I would suggest introducing a few greens/ veggies as well, so that she has enough energy to grow while cutting back on the nuggets, but I wouldn't want to make too many changes all at one time.
So for now I would start to slowly swap decrease the amounts if necessary, and mix foods - I would suggest you find one that is a lot higher in fibre than it is in protein, and start mixing the two together, slowly increasing the new one and decreasing the old one over about 10 days.
Good luck x