Also, do not leave a dog in a closed car. This is as applicable to the quality and amount of food as it is to the bloodlines of his ancestors. So, don't skimp. A large breed grows fast and has a lot of developing to do in a short period of time. Although a Great Pyrenees may mature slowly, your puppy grows fast and needs wholesome, nourishing food.
Nothing takes the place of a good quality balanced dog food, or puppy food for young dogs.
Dogs prefer consistency. Do not give bones for these can splinter and thus be dangerous. Feed regularly prepared, fresh food at set times and in clean dishes. There are many excellent commercial dog foods available to canine owners, never feed generic dog food. See your veterinarian on schedule to check for worms, other parasites, heart worm, etc.