At last. You can all sleep easier tonight. Closure on the Trader Joe ferret issue.
We received this mail from the ferret finder:
Thanks for the suggestions and for posting it on your blog. We actually took the ferret to the place up north that someone mentioned in the comments (and we had multiple other recommendations for), The Best Little Ferret, Rabbit, and Rodent House — or some such name. I called Animal Control and left a “found” listing, as well as posted it on Craigslist and multiple neighborhood list-serves. The ferret didn’t have a microchip, but I hope he finds his owner or another happy family soon. Thanks for your help and concern!