Hi.
I know a lady who used to do rescues and she said she had a few that lived to 10 or 11. That was out of about 64 ferrets. The oldest I've ever heard of was 13, but that came from the owner on facebook, who i did not know personally. Could be a total fabrication.
My wife and I have had 25 fuzzies. We know that 2 have made it to 8, and possibly a couple more whose exact ages we didn't know. I have rescued a few myself. All that said, the average life expectancy I have seen, whether mill or private breeder, kibble or raw fed, is 6-7 years. I moderate this and another popular ferret forum and have been on forums since 2008. I know people who spend thousands of dollars on expensive food and testing and treatments when they get sick but 6-7 is the average.
I would guess that Eddie was 7, and possible Rocky and Moe. Ours have all been Marshall ferrets except 2. Kahlua was probably a Marshall's (ear tattoos) bought in Canada and made it to 7 with adrenal and later got insulinoma. She lived to just over 8. Prissy is a Real Canadian and going on 9 now, but she is almost blind and deaf and incontinent and has a hard time walking. She looks old. We are surprised every morning she wakes up. She is the oldest we've had that we know. Jaffa was from a private breeder and died of adrenal at 6 years 2 months.
None of this considers accidents, intestinal blockages from eating stuff they shouldn't, escaping, juvenile lymphoma, or sudden unexplained passing. 75-80% of them will get one or more if The Big 3 (lymphoma, adrenal disease and insulinoma).
Sad, and I really don't want to scare you, but that's ferrets. I sincerely hope that you and yours live long and prosper.
<message edited by unclejoe on Wednesday, November 18, 2015 10:26 PM>