A one-month-old puppy is old enough to begin eating puppy food but is not old enough to be weaned from its mother's milk or a milk replacement. Because a young puppy is not yet used to chewing hard food, soft-textured foods are best at first.
Most female dogs begin the process of weaning their young when the pups are three or four weeks old. At this time, an owner can begin introducing small amounts of soft puppy food or dry puppy food that has been mixed with warm water or milk replacer. As the puppy grows older, it can have larger amounts of food and can begin trying dry food. Once completely weaned, puppies should continue eating dog food that is made specifically for puppies until they are at least 12 months old, unless a veterinarian advises otherwise.