I have 6 week old baby labs, they have been eating on their own for about a week, mother lets them suckle once in awhile but not very often. My question is, we have them on Purina puppy chow with mothers milk formula in it, I noticed today that some of the puppies are vomiting it up, even hours after they ate, they have no discharge in any of their eyes, ears or nose. They are showing no signs of lethargy, today they were running in the yard like a normal puppy. Should I be concerned?. Plus we are placing the puppies with their new families this weekend, is it to soon?.. They are eating on their own.