Puppies do normal biting, play biting, mouthing, and nipping conduct since they take a look at their surroundings and learn to interact with other dogs and people. Separation stress and anxiety is a standard problem https://www.google.com/maps/d/u/0/edit?mid=1Loaxd9o4I0MvP5CHmLZ6bvGvzslqEQw&usp=sharing