Lisa -
 
The sifting liners won't work with ferrets.  The premise of how these
liners work is that they are used with clumping kitty litter, and when
sifted, the clumps that are formed aren't small enough to get through
the holes in the liner, whereas the rest of the litter is.  There are two
reasons you can't use them:
 
1. You can't use clumping kitty litter with ferrets.  About the only
kind that's good for them is pelleted, low-dust litters.  The reasoning
for this is twofold; the dust that is made by these litters is harmful to
ferrets' respiratory systems, and the tiny pieces of litter can easily
become impacted in ferrets noses, requiring trips to the vets, and hefty
vet bills.
 
2. Even if the litter worked, you wouldn't want to put a soft plastic
like this in a ferret's cage.  They could ingest a small piece of it and
it cause a life-threatening intestinal blockage.
 
If you have been using regular kitty litter, I recommend any of the
following as litters:
"Yesterday's News" brand pelleted cat/small animal litter, wood stove
pellets (you can get from any tractor/farm supply store), "Woody Pet"
brand pelleted litter (also from tractor supply stores, and pet stores),
and rabbit food pellets.  I've used all but the rabbit food, and can say
that they work very well.
 
~Keri
[Posted in FML issue 4449]