One of the known things, which is also why I don't know many vets who'll neuter or spay a dog under six months, is that sexual hormones are nessisary, especially in males, for proper and full adult growth. Early neuter ferrets lack the muscularity and sexual dimorphism of non-neutered or 4 months-1 year neuter of other ferrets. Another concern is that they're small animals and sometimes the job has been incomplete, especially with females, when done by techs doing hundreds of animals at a large breeder. For some time, Hagen ferrets in our area were constantly going into heat, which the less informed owner was left doubly unprepared for since they had been told their animal was neutered, as were the local vets who often weren't used to ferrets and didn't realise it was a case of part of an ovary being left in. The other health concerns are things I don't feel qualified to comment on, but I think both these reasons make it reasonable for people to prefer ferrets to be neutered at an older age. Melissa Smith (nee Drake) http://www.blueskunkland.com/ferret (the Wooze Crew) http://www.blueskunkland.com/ferrettoons (over 20 designs on over 30 products for the holidays!) [Posted in FML issue 3996]