First off ferrets do go through weight gain and loss cycles to help compensate
for temperature in the summer and winter. If this is definately due to illness
then you might try a small amount of Nutrical each day. About a 1/3 inch ribbon
is what we give at the shelter when we get a really thin ferret. Don't overdo
it though as Nutrical is a bit high in sugar. Also, don't give Ferretone of
Laxatone along with this since Nutrical has a fair amount of vitamin A in it
and you don't want to od the ferret.
 
[Posted in FML issue 0739]