I didn't actually cat-proof our ferret's litterbox.  We did the whole
cage, to keep the cats out of the food.  To start with, our ferret's cage
is about 18 inches off of the floor, so we made them a set of stairs to
get in and out.  When the cat problem appeared, we added a wall to cover
the opening (wide but low) with a small hole that a ferret can get
through, but not a cat.  I'll try for a (dreaded) ASCII graphic...
 
 
                       imagine cage up here
                   __________________________
                   |                        |
                   |        __              |<- board to cover cage door
                   |_______|__|_____________|   with hole for ferrets
            ferret hole on  ^
           top of steps
 
I hope this isn't too confusing.
Liana Winsauer
[log in to unmask]
and Neko and Totoro and Akira
[Posted in FML issue 1141]