There are certainly other things that cause this.  For example, my Jasper
had it as a first symptom of ECE--it was also green, though, so that
would be easy to spot.  That was years ago, and I was on the phone for a
couple of hours before I found someone (a nice lady in Florida) to tell
me what it was and advise me.  I've seem scepticism about whether this is
really something that goes with ECE, and I have to say that it certainly
was in my case.  I didn't know about force feeding then, and the only
thing I could get him to eat or drink willingly was water in which
raisons had been soaked.  The hydration and calories got his energy back
up to where he would eat on his own.
 
I'm just saying it doesn't have to be a blockage.
 
--Clover
and the rezweezils: Buddy, Cookie, Yogi, Butter, Buster (aka Fatboy),
Lew, and Marissa
 
"Always selling quality bedding and other goodies to help the ferrets!"
http://search.ebay.com/_W0QQsassZwclovergalQQhtZ-1
[Posted in FML issue 5173]