They do make ferret-sized e-collars. If you are going to a vet who
specializes in small animals, they certainly should have them in stock.
If not, ask them to order some.

I never knew they made them so small until one of mine was sent home
from surgery with one on.

You can also make one from x-ray film or any similar, bendable plastic.
Just make sure to smooth the edges or put tape over them, so it doesn't
rub.

Katharine
Florida

[Posted in FML 6636]