Hi.  I had a suggestion that I got from this list for keeping ferst from
climbing standard baby gates if you can't afford or use Plexiglas.  You can
buy a large-diameter piece of PVC tubing/piping (it's plastic) that is the
same length as the top of the gate and slit it all the way down one side
lengthwise and affix it to the top of the gate like a cap.  Then, even if
your ferrets climb the gate, they cannot get a grip on the top to launch
themselves over to the other side.
 
Good luck!
 
-April
[Posted in FML issue 3481]