I have also heard that bunnies love grenadine (that flavoring used in cocktails). The veggies is a good way--I do that too when I'm worried about GI issues during molts when they eat a lot of hair.
I don't think netherland dwarves in particular are more susceptible to it, but I know some breeders will find that a particular "line" of related bunnies will have it. I assume since bladder sludge is what a geneticist would call a maladaptive trait (some thing that doesn't help the animal survive better), that it is more common in lines that are more inbred. Traits like that are usually recessive so they come out when related bunnies are bred. Because Nethies are a special breed with some other maladaptive traits (like that flat face and tiny ears, along with a predisposition for tooth problems), it would make sense that sludge could occur more often in them. Some of the traits that make a nethie good on the show table are rare and a breeder will have to breed related bunnies together to get all the traits they want in a single bunny. Also, depending on where you got her, she may have been from an accidental litter between relatives. At the shelter I help at, a lot of bunnies come from accidental litters where someone had siblings and didn't know they were sexually mature until one had a litter--some people don't even know their bunnies' sexes until a bunch of babies appear! So, her genetic background could be pretty murky and it's hard to tell. I know responsible breeders don't do sibling breeding, but they will do relative breeding. They will also take a bunny out of the breeding program if they develop a problem like sludge, but not all breeders are responsible and not all can find sludge until they've already had a few litters.
Sludge and stones are definitely related. Amy's Chase had stones first, and then sludge, if I remember correctly. It would make sense that a large amount of unresolved sludge could form into a stone over time.
I don't think sub-q's are too stressful, but they can be difficult to give if you don't have a lot of experience. The solution itself also has to be stored with care, and the fluids need to be warmed to body temp before injecting, which can be stressful. Myheart has a bunny named Luna with chronic kidney stones, and for a while, she was getting a lot of sub-q's administered at home, either daily or every other day. She has improved a lot and didn't seem to be too bothered by the sub-q's.
Good luck!
