Hi Maggie,
Thanks for your question.
I appreciate all of the detail you provided in your question but we can’t launch into treatment without knowing what it is that we’re treating, I think you need to take a few steps back and consider a diagnostic test. I would recommend that you speak to your veterinarian about performing a fecal test to look for parasites. There are many different types of parasites that are very common in young dogs and especially ones that were housed in shelters. In fact, given the symptoms you describe, I would be surprised if your dog didn’t have an intestinal parasite. Consider this….imagine if your dog has a parasite. All of these changes you’ve made to diet would not treat it at all and the problem would just persist.
I hope this helps.
Dr. Clayton Greenway
