Passing a blockage large enough to cause the degree of symptoms and
imaging you describe can cause tearing of the GI tract which can be fatal
in and of itself.  That actually was one of the things considered as a
possible cause of death for Scooter when he passed on in his last hours.
The one he passed was substantially smaller than ones we've seen removed
by surgery, too, but it was still big enough to have torn him.  From your
description this ferret sounds like surgery is needed ASAP.  Don't forget
that blockages that are complete or nearly complete can cause a build-up
of toxins and other problems so the longer a serious blockage remains
the less likely even the needed surgery will save the individual.  The
way your post reads that is a situation in which emergency surgery is
commonly done and we've been there ourselves as have many others.  What
is advised by a ferret knowledgeable treating vet?
 --
 
Human food: watch out with true licorice/licorice root; it is too
dangerous for animals prone to hidden circulatory disease.
 
As usual, I am not a vet, but have had ferrets in the family for 20 years
and have been involved in an assortment of ferret health related projects
for most of that time.
[Posted in FML issue 4067]