other than increased water consumption, I am not aware of any foods that can help your rabbit other than avoiding high protein foods (which you should be doing anyway) and free choice green leafy foods ( which you should also be doing anyway- get more water in the diet that way). I would be very wary of giving a rabbit with CRF pellets as these have zero moisture and tend to have excessive protein. NOt sure how vitamin B helps, but it is pretty harmless.