John, I suspect that the barley helped some of her shelter ferrets
for the same reason that some ferrets with IBD are helped somewhat by
unsweetened pumpkin puree: fiber just does help some ferrets' ill
intestinal tracts be able to create normal or nearly normal stools.
Some others are helped only short term while others are not helped at
all.  (Now, we people can be helped a decent bit more by fiber often;
there is a new Freihofer (sp?) bread, "double fiber whole wheat" which
makes our own digestive tracts here in our family feel and act about 25
years younger than they are.  We don't have any stock in the company,
nor do we make any money from them, but we sure like the way that bread
type so greatly agrees with us.  Personally, people have asked me if i
lost about 10 pounds, but it was all just inflammation going away.) So,
anyway, yes, some ferrets have their intestinal tracts soothed by fiber
just as many humans do, and i suspect that is the effect the barley
content was having.

-- 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 5276]