I have only come across this problem once in 14 years. With me, it was with a male charcoal kit which I aptly named Piddle. At the time, I called lots of experienced breeders to see if anyone else had heard of this problem. I found one other breeder (Brenda from Brenvics Chinchillas) who had dealt with a similar condition (I have since heard of several other cases in the UK & US in the last 2-3 years).
I have also recently read of the condition in a 1960’s Ranchers Handbook, where the kits are described as “wetters.” It appears “wetters” were first documented in the 1940s on a ranch in Virginia, USA.
It is an incurable genetic deformity affecting the urinary system, which causes incontinence. The entire belly is usually urine-soaked.
I did try to keep my affected kit comfortable by ensuring that the fur was clipped away from his parts, as it was only getting soiled and matted. Then I washed his belly twice a day with a mild antiseptic solution (hibiscrub), diluted in warm water. He was then thoroughly dried with a hair dryer on a cool setting (bought especially for him). I then applied some Sudocrem or Dermocrem cream on his skin, as he was getting sore (urine scald) with his incontinence.
I did take him to see a vet, who said there was nothing he could do to help (as a chinchilla is too small to perform a “re-plumbing” operation on).
Piddle became so miserable (despite my best efforts to keep him clean and prevent his skin from becoming urine-scalded), that it was decided to have him put to sleep. It is not much of a life to be continually soaked in wee!!
Hopefully, this genetic condition will remain rare, but a rethink of breeding practices needs to be carried out if it crops up regularly in any breeding herd.
Note: Mild incontinence can also be caused by infection (i.e., cystitis) or bladder stones. Veterinary treatment/diagnosis is essential. This mild (temporary) incontinence usually clears up on recovery.