We have had ferrets whose spleens were removed. Unless rupture is imminent the vet will carefully pat the spleen to remove blood back to the body. None of the ferrets we have personally had in over thirty years whose spleens were enlarged had problems with removal, but that can vary depending on what is present, care after surgery in the first few weeks, etc. All did better without the huge spleens. As usual post-op recommendations like not climbing or being active for around two weeks apply since those can cause fatalities. Ditto keeping reasonable hydration, and otherwise providing safe care. You can find such tips in the archives of both the FML and the FHL. Look for content containing words like postsurgical. Also seek content containing spleen and surgery or similar phrases. The middle word in one of those ferret lists is mailing while the other one is health. [Posted in FML 7295]