If your ferret is like any that I've ever seen, they fancy themselves an
interior decorator.  In no time at all in his pen, mine would have the litter
box pushed over by the door, the water bowl dragged accross the floor
(spilling most of the water into his bed), and the food bowl in the corner
where the litter box used to be.  I didn't want to permanently fasten the
litter box, etc to the pen because then they would be hard to clean.  The
solution that I found that works great is to buy two of everything.  You may
notice in the store that most litter boxes and bowls are "nested", ie.
stacked inside of each other.  I screwed the first litter box to the floor in
the corner and then put an identical one inside of it.  It's a tight fit and
so far it either hasn't occurred to him or he hasn't been able to take them
apart, while it's easy for me to grab the top one and lift it straight out.
I did the same thing with the water bowl.  If you have a wire cage, you could
fasten the first litter box by poking holes in the bottom and wiring it to
the cage floor.
 
[Posted in FML issue 0583]