No one can tell for sure what is going on with those dark green poops with
slime, except for your vet.  Anytime there is weight loss it is cause for
concern and a visit to the vet is needed ASAP.
 
The poops you mention with slime are usally ECE and almost all pet store
ferrets have ECE.  When bringing a new ferret home, it is a good idea to
have it quarantined and get it to the vet before you start the
introduction process to the rest of the clan.
 
You should probably take your exitisting ferret(s) in also, because they
have been exposed too.  Don't feel bad it's very common and easily cured.
Get the gang to the vet ASAP.  I hope that helps.
 
Kim the Oregon one
 
Kim Reyes
Residential Real Estate Specialist
Direct (503) 380-4195
Toll Free 1-877-490-2595
http://www.kimreyes.com
[Posted in FML issue 3799]