It doesn't bother me so much that she is biting my son. She is constantly after him. She is not biting maliciously either. She is happy when she does it. She tries to bite me too when I am holding her. She bit another little girl in my care. I felt bad having to tell her mom about it. I placed the biter on a chair for timeout, but I don't think she understood why she was there.

I will be the first to admit that my oldest son is very rough and not always nice to the other little ones. He is now in school. (thank God). My 1 year old though is the easiest and sweetest little man, but he is always the first one the other kids lash out their anger on. The 2 and 3 year old are constantly ripping toys away from him (and sometimes eachother), pushing, and hitting him (sometimes). He still loves to play with them and easily forgets the pain they inflict on him when they are frustrated. But my little guy is absolutely petrified of this 12 months old who is constantly after him to bite him or pull his hair. He just mastered walking, so he does not know how to get away from her. I don't even think he understands what is going on. How do you teach a 14 month old boy to defend himself? I've been bit by little teeth and it hurts! Lol.
When I place the 12 moth old in a playpen, she becomes hysterical. I am not sure that I want to make the playpen a bad place, though I am starting to think it might not be a bad idea. It will give her a timeout and give me time to play a little with the others. I am going to try the soother too. I do have one here for her.
Thank you for the great advice!