Milk coming out of the puppy's nose after feeding?

We have 3 orphaned Boston Terrier puppies we rescued without a mom at 2 weeks old. We have been bottle feeding them all with a formula recommended by a vet. Now at 3 weeks, they have regained their energy and all eating well. We have one runt of the littler that eats extremely fast and always the first to finish his feed out of the other two. Yesterday, all of the sudden, the milk started coming out of his nose, so we changed the nipple on the bottle to a much smaller one to slow him down. Now at each feed, he will finish his milk, but once I place him with the other 2 pups, milk started coming out of his nose and he yelps like he is in pain. I took him to 2 different vets and they said that there is nothing they can do, since the puppy to so small. I have read that the issue could be cleft palate, mega-esophagus, or feeding too fast, but I don't know what to do. I even broke the feed up in small feeds, but still milk comes out of the nose. Any suggestions?