We just rescued a beautiful, 2-year old Golden and we already love her dearly. BB does the usual barking when someone comes to the door but calms down quickly and is friendly with strangers. Our concern seems to stem from a specific situation: when she is confined by herself - in the house, or a kennel - she will become almost vicious when someone approaches - even with people she knows. I boarded her at her foster home overnight recently and when I went to pick her up, she got up on her hind legs, threw herself against the door and barked and growled at me. Once I opened the door, she was fine. The other day when she was in our house alone, the neighbor - who BB knows and loves - came to the door to take her for a walk but BB threw herself at the storm door and was so intimidating, my neighbor was afraid to open the door. She seems to do better if she can't see who's at the door. I'm confused at her behavior because she's an otherwise sweet and affectionate dog. Can anyone explain this behavior? And any advice for changing it?