H cold have a dairy allergy but too hard to tell. He is still a pup so he might just be adjusting to the food change if yo changed it from what the breeder had him on! Coop had ice cream poo for what seemed like forever....this means months lol. Then he finally had solids, I hated going out there and cleaning it up cause it wold get all over the grass and make m want to ! I knkow people say try canned pumpkin that helps with the runs. Also have you had his poo tested for parasites that cold also be it. Puppies get parasites easy so if you haven't I wold recommend taking a poo sample into your vet. But I would give him some more time also. New environment, new food, he is just adjusting If none of this works cut the yogurt and cottage cheese or change to a different dog food like fromm....fromm is a popular one for the bullies!