I think you should consult your vet to make sure she's parasite free, and okay healthwise. They can perform some tests to figure out what she has, if there is something wrong. She could be allergic to something, or maybe there is not enough fiber in her diet? She might have irritable bowl syndrome? They will be able to help rule those out. If nothing wrong, I think you shouldn't worry. Some puppies just have soft stools until they get a little older. It's like human babies, they pretty much have slop for poop until... 1-2 years old? (Never really been around babies, but hear of the mush poop. I just assume that's the age poop becomes solid, it might be younger, lol). My puppy usually had pretty soft poops, formed but still squishy (and occasional diarrhea) until she was about 9 months old. Vet said she was good healthwise, and she never seemed to be in distress. Now that she's older, she eats Acana and has firmer poops, but still has the occasional softy/mushy almost diarrhea-like. Is your dog a nervous and anxious dog? Anxiety and stress can cause stomach distress, soft poops, and diarrhea.