We have a 12 week old female Newfoundland puppy, we also have a 9 year old female Aussie. The puppy keeps jumping on the adult's back and biting her neck and ears and when we make her stop she backs up and barks at us (as if to sass back at the no) and if we grab her to make her stop picking on the older dog she bites at us. I realize all of this is the way she engaged in play with her littermates but it isn't acceptable play now and I don't know how to stop it. When walking next to her she bite at your clothing and in the process sometimes also connect with skin.
This behavior isn't once in awhile, it's constant as long as she's awake and near the older dog. Our Aussie is getting extremely nervous and stressed over the puppy because of being attacked every minute she's near her.