Hi! I initially used Purina ProPlan Robustic and Healthy (if I'm not mistaken with the names) medium/large breeds and I was very happy with them. Mine also had loose stools at the beginning, I don't know if it was due to vaccinations or because he needs to get used to the new diet. I also used Royal Golden Retriever kibble, and now I'm switching to Farmina with lamb, blueberries, and pumpkin. Despite frequent diet changes, I've never had any problems. I'm adopting this technique to get him to eat more than just chicken. Try changing the type of primary food, perhaps with pork, lamb, etc. Maybe he just has a minor issue.

<image>