My dog has always been a biter. I'm pretty sure it's just playful but it really hurts. It took us forever to get her to stop using us as her chew toys but we finally got her to stop and now out of no where she's started biting all over again. It's getting to the point that no one wants to be in the room with her. My children are out of school so we don't go on regular walks as much but she still gets plenty of exercise with the kids playing with her and she loves to run the fence with our neighbors dog. My husband said he saw new teeth coming in which I suppose could be the problem. We tried doing the time out with her again which seemed to make things worse so I tried the positive reinforcement by giving her a "good girl" and/or treat when she would stop when I tell her to. So far it's not working. Is this normal behavior? Any suggestions on how to fix this? We had actually considered getting another GSD so that she would eventually have a playmate to occupy her but was afraid the age difference might make a problem or having a 2nd dog just might be twice as much trouble. Any opinions on that matter?