He's acting like that because he is scared and insecure around the children and the barking is a warning by a likely worried little dog. Quite a few small dogs are like that. He doesn't believe you can keep him safe in their presence or he would not act like that most likely.
__________________ Jeanie and Tibbe One must do the best one can. You may get some marks for a very imperfect answer: you will certainly get none for leaving the question alone. C. S. Lewis |