The best food for any puppy is the one that best meets his nutritional needs for growth, development and energy. Small dogs and puppies have special needs, and you can meet these by feeding your pup a variety of foods in combination and following your veterinarian's advice.
Best Commercial Kibble
Dry dog food, called kibble, is convenient and relatively inexpensive, and it's suitable for a miniature Schnauzer puppy. Kibble is easy to feed, easy to store and does not spoil quickly if kept dry. To find the "best one" for your mini Schnauzer, read the labels on as many brands of kibble as you're willing to lift. First, look for a statement by the Association of American Feed Control Officials (AAFCO) that the food is nutritionally adequate for puppies or all stages of life. Like the nutrition labels on people food, the ingredients are listed in order according to weight from highest to lowest. High-quality kibble has meat or meat meal in the first 3 ingredients; the best will specify the type of meat (chicken, beef, lamb). Meat byproducts should be high in the list of a good kibble; byproducts come from parts of the animal people may not like -- liver, blood, brains, chicken lips -- but dogs love them. The next ingredients should include complex carbohydrates, such as whole grains (preferably rice, rolled oats or barley) and vegetables (carrots, green beans and pureed pumpkin are good, but beets or beet pulp are not, because they have too much sugar). Next you should find fats and oils; look for fish oil, flaxseed oil, canola oil, chicken fat and safflower oil. Vitamins and minerals should be listed, too. The last ingredients should be preservatives, artificial colors, and stabilizers; these include anything from corn syrup to cheese to unpronounceable chemicals and have to be approved by the FDA or generally accepted as safe.
Best Commercial Canned
The best canned dog food is likely to contain more protein than even the best kibble and will probably be more attractive to your puppy because it smells and tastes better. Read the label and look for the same things you would look for in kibble. Buy small cans made for small dogs because it spoils faster than kibble; refrigerate it once opened and use it up within two days. Mix canned food with kibble so your puppy gets the benefits of both.
Best Commercial Fresh
Fresh dog food is now available in special refrigerators in pet mega-marts and grocery stores. The label should show that it is AAFCO approved and contains only the desired ingredients, and all of them. It comes in rolls or loaves that you'll need to freeze if you don't use it within a day or two. Check the calorie count, which may be higher than that of kibble or canned food, and adjust the serving size to keep your puppy from gaining too much weight.
Raw food, including meats, fruits and vegetables, works for some dogs, but issues concerning contamination and disease transmission exist. If you want to transition your puppy to a raw diet, wait until he is fully grown and make the change very gradually. There will be no AAFCO label, of course, and the ingredients are up to you, so stick to those approved for humans and ask your veterinarian about vitamin and mineral supplements.
Making your own dog food gives you complete control of your puppy's diet. Recipes abound in books and on the Internet. The usual ingredients are pretty much what you'd cook for yourself -- lean meat, fresh vegetables and rice (white or brown). Again, consult your vet about the need for supplements.