Jennifer, Any chance that your ferret has been chewing on a dyed piece of clothing or paper with soluble ink? Have you checked the kibble (if using kibble) or treats for any dyes? Has the ferret gotten hold of any licorice? Any pills? Check your litter pan material, is the ferret ingesting newsprint pellets with ink that is causing the discoloration? What if any is the vegetable content or source within the kibble? High amounts of vegetable matter could be causing discoloration. How "green" is it? Cheers, Kim [Posted in FML 6241]