How to Control and Direct Puppy Chewing Behavior by Dr. Marty Smith, DVM Drs. Puppies don't understand the difference between new and old.
Dogs learn through their mouths.
They are naturally inclined to use their mouths whenever they can. Fortunately, most destructive chewing behavior can be prevented or controlled. Puppy-proof the confined area. If possible, remove all items your puppy can chew on, including socks, shoes, furniture, plants, etc., from any area in which you confine your puppy. Tape over electrical outlets and make sure electrical cords are out of reach.