Not terrible looking, if that is only occasional (not every poo) it could be a cecal, which happens about every 8 to 10 poo's, usually is runnier/creamier/more tarry, and smells worse than regular poo's. But I would decrease the treats, or even stop for a week, and see if there is any improvement. If not, and you are seeing this more than occasionally, it would probably be a good idea to take a sample into your vet (assuming you have one that will do it) and have a fecal float test done to check for parasites.
If you 'must' give treats, really, really try to keep it to less than 10%. Too much of a good thing is not a good thing.
If you 'must' give treats, really, really try to keep it to less than 10%. Too much of a good thing is not a good thing.
