I'm sorry to hear that a little kit out their has an icky belly.

maybe the "stress" causing the ulcers was going on a raw diet to begin
with and maybe that is why "the vet" suggested switching to kibble.
Just saying.....

I would highly recommend seeking out a second vet for another opinion.
12 weeks with ulcers seems so young. It would be good to rule out other
possibilities.

If you do go back to a kibble based diet and want to assure your little
one gets plenty of protein there are other option to raw. My ferrets
have really thrived on what some of us in GA call "Love Gravy" made by
a local ferret diva momma, Florence Love.

Because none of us here on the list know the fine details of your kit's
health, please seek out another vet's opinion or supply a more back
ground on your little one. I have found the FML a priceless resource
for my ferrets. There are some on this list that have very strong
feeling regarding certain things, i.e. the raw vs kibble or caged vs
free roam. Thankfully everyone of this list appears to have ferret
care as a top priority.

Best of luck with your baby.

[Posted in FML 6616]