I have nine ferrets, and use the playpen.  I have it set up four panels
by three panels, so I guess I added two expansion sets to it.  (It's been
done over a couple years, so don't recall exactly how many it originally
comes with.)
 
It's escape proof (for my ferrets anyhow, a couple of which are
climbers/jumpers) and with the size I'm using, it seems to be plenty of
room for them.  I have tubes, literpans, food and water, bedding, toys,
etc. in it, and there is plenty of room.
 
My ferrets are all older, the youngest is about five, and the oldest
is age unknown but ancient, I'm not sure that long-term it would be
appropriate for a couple younger ferrets, but for a month, even if
you have six month olds in my opinion it's fine.
 
Anne
[Posted in FML issue 4532]