We have a few climbers here and it is a very scary thing they they have
no fear of heights.  Our solution was to get old x-ray film and cut holes
in the corners and use zip ties to the bottom level on the out side of
the cage.  It is easy to wash and doesn't cost a fortune and usually can
get from a vet or hospital.  Plus light weight so doesn't make the cage
heavier like Plexiglass would.  I hope this is a good solution for you,
I also have skunks and it keeps them out of the ferrets food.
 
Katrina Owens and crew
[Posted in FML issue 5229]