Risa, we have had a pair of Stokke Balans Tripose for over 20 years.
You DO need to know that the ferrets are not running around near their
bases before shifting position -- same as for a rocker.  The tripose
are not made any longer, but a 4 position one "Gravity" is:
http://www.stokkeusa.com/movement.htm
 
We used to have an old fashioned sort of recliner which I wish we still
had but someone stole it.  There was a separate hassock, and the back of
the chair was attached at the base, but the armrests extended back and
had slots in them.  The back of the chair could be moves to whichever
position a person wanted, for up straight, to almost laying down and
it was a very comfy chair to sleep in.  This sort of approach would be
incredibly safe for the ferrets, plus a sturdy chair like that will
last forever.  If we ever live in a larger place I will have to have
one again.
---
 
When uroliths are present it is essential to find out what TYPE they are.
The most commonly seen ones in ferrets are struvite stones which also go
along with the pH being too alkaline.  Second are cystine which go along
with the urine being too acidic.  Those two have OPPOSITE causes and
opposite approaches.  There are some more rare types with causes that are
very different from either of the other two.  If stones were not tested
then get a urine pH because usually that will help design the medical
approach.  Cystine stones in ferrets are currently under study by a team
at U.C. Davis headed by Dr. Michelle Hawkins.  She is also heading a
team studying some possible genetic vulnerabilities in ferrets.  If
anyone has a ferret with cystine stones let me know if there may be
specimens and I can get you in touch.
 
-- Sukie (not a vet, and not speaking for any of the below in my
private posts)
Recommended health resources to help ferrets and the people who love
them:
Ferret Health List
http://www.smartgroups.com/groups/ferrethealth
FHL Archives
http://ferrethealth.org/archive/
AFIP Ferret Pathology
http://www.afip.org/ferrets/index.html
Miamiferrets
http://www.miamiferret.org/fhc/
International Ferret Congress Critical References
http://www.ferretcongress.org
[Posted in FML issue 5295]