I honestly think you should either keep this ferret, or find him a better
home.  From what you have said, it sound like the original owner isn't
concerned about the ferrets well being.  The fact that it took several
days for her to even call you once she knew where her ferret was doesn't
sit right.  If my pet had been lost, and I knew who had them I would have
been there that night to pick them up.  If I were you, I would keep the
fert and either tell the owner they aren't fit to care for it, or to
avoid any arguements tell her the ferret died and the body has already
been disposed of.  In any case, I think that is what I would do if I
were in your situation.  Let us know how things work out for you :)
 
Laura
[Posted in FML issue 4531]