If I were you, I would try to find another vet who might be more ferret
knowledgable.
 
Prolapses can be caused by a variety of medical conditions - there is a
particular condition - Proliferative Bowel Disease, I think, that causes
a chronic prolapsing, straining, in/out of the litter box, etc, that can
be helped with proper antibiotics.
 
Foreign bodies causing obstruction as well as improper diet can cause a
prolapse as well.  IMO, this is definitely worth pursuing further.
 
Debbie Riccio
WNYFLFA
Rochester, NY
[Posted in FML issue 1707]