bunny straining to pee/cakey bladder sludge

Question
Just moved w/ house bunnies to new city/country a week ago & noticed F, 5 y.o. spayed bunny is straining to pee & hv seen thick, clay-like, dried sludge in x-pen. Smokey is part of a trio, w/ a 10 y.o. F & 5 yo male rabbit. Not positive she is 1 with sludge as would hv thought 10 yo bunny more likely to get it. Have spent 2 hours calling around looking for a rabbit savvy vet, but haven't found one that can see Smokey today after trying 12 referred vet practices. It will be Monday or Tues b4 a vet can see her.
I can get my hands on subq bag from a local rescue, tho. Should I give bunny sub-qs for a few days until I can get in to see a rabbit savvy vet or is this dangerous? Smokey has no history of health problems at all & is eating normally. Should I separate her from the trio to monitor her more closely? Am feeding wet veggies to encourage hydration & trying to keep her moving around/exercising so the sludge doesn't settle in her urinary tract. Any other advice? Pain meds? Gentle bladder massage?She doesn't seem to be in pain & is acting otherwise perfectly normal. Thank you for any guidance u can give me.

Answer
Dear Iris

I would not separate her from her group, as this may cause them to un-bond (fighting and misery upon reintroduction) and also cause depression on the part of all three.  Not good for a sick bunny.

If she's straining to pee, then there's something wrong in her urinary tract, whether or not she's the one with sludge.

As long as her heart is in good shape, subQ fluids should help her clear the sludge.  If you suspect sludge, then you can administer fluids, wait about 30 minutes, and then gently agitate her bladder by tapping it from below with enough force to jiggle the contents and get the sludge into suspension for easier evacuation.

Once you find a good rabbit vet, radiographs will reveal whether she has sludge.  Your vet can suggest appropriate therapy.  (Note that, apparently, urinary tract infections can foster sludge, and vice versa.)  Ask about learning how to safely express her bladder, if your vet thinks this is a good idea.  If you jiggle the bladder to suspend the sludge (after subQ fluids) and safely, gently express the bladder, that can often help keep the problem manageable.

I hope this helps.

Dana