I had an almost identical experience to yours.  I had the window open
airing the place and it didn't occur to me that one of my girls would go
out the window. Anyway, next thing I know, I see Bee out on the window
ledge (yes, she keeps herself very busy) and as I'm running over there to
pull her in I saw her fall....three stories. I thought for sure as I went
tearing down the stairs and out the door that I would find a dead
ferret.  When I got there she was kind of frozen in the same position,
but when I picked her up she sememd to respond and in a couple minutes
she was fine.  I called the vet and they told me what sypmtoms to look
for for internal injuries and such and I kept a close eye on her, but she
was fine. I was amazed.  That was a couple months ago and she's still a
busy Bee getting into more trouble...
 
Jena, Bee, & Bearsley
 
p.s. Bee still has no fear of open windows after her three flight fall! I
have to watch her like a hawk if I have the window open!
[Posted in FML issue 1189]