Haydz

your pup will be fine as others have said. most of my puppy classes i attend have breaks for puppy play called 'socialisation' work lol. gives ur pup the rest they need, and playing helps keep their energy and drive up, as well as even more advatages liek learning bite inhibition and impulse control

they are just pushing the importance of dog safety at such a young age, Especially since you can ruin a dog in its puppy days. hypothetical situation: 9week old LARGE breed dog is taunted by kids on skateboards... you as the owner never find out until around 15mths you are walking your dog, kid on a skateboard flies past and your dog bites to the bone.. Dead dog and kid in hospital are the result. i just feel its too risky to let such a young dog on its on in public, you never know what could happen. Aceing puppy school is more a gauge of you as a trainer to understand what your dog needs to respond to training. So perks to yourself as well as your dog. edit: for grammer

Phoenix used to do that to her lead. I would simply growl in bad dog voice and pull the lead up, so everytime she went to bite she was strangled (for lack of a better word), so she would get an annoying jerk. Being a puppy Link is just testing what he can get away with. You may need to do some social walking training (the turning away everytime they pull as wizzle suggested), maybe some corrections and treats will show link what is acceptable.

could be simply that you have a healthy puppy. or your giving it a premium food so it has lots and ots of energy and calories to burn. have you had other dogs on cheaper food maybe thats the difference I work at a petstore and havnt heard of that before. however corn can affect dogs in a wide variety of ways. mainly skin conditions though..