Hi, Sorry to hear about Boo Boo's odd feces! Can I get a little more information from you?
How long has she had the grey, slimy stool? Is there any form to the stool at all or just very mucousy? Any vomiting? I assume your vet has checked it for parasites--anything seen? What diet is Boo Boo eating? Has your vet prescribed any treatment and did it help at all? Is she gaining normal weight or getting skinny?