I have them, too, at least twice a month, if not more.  Mine usually center
around the premise that they have somehow escaped, someone has let them
loose or that something is hurting them.
 
At first they were terrifying, and I would wake up crying, and immediately
go to check to make sure they were still there.  Especially the one where
the cat was running away with Boo Boo!
 
Now, since I recognize why I have them, I am able to control them.  Once
the dream sets in and the ferrets are loose, I make a significant effort
to catch them, and I always do.  Now, the hard part in the dream is trying
to hold all 8 of them at once.  8)
 
 Julie
[Posted in FML issue 2938]