We have a 4 month old male boxer who is doing so well and I don't want him to develop bad habits if I can help it. Behind our fence we have a couple of "yipper" dogs who go nuts every time Rocky goes outside and he barks back at them. How can I stop this? I do not want a barking dog. I don't want to not let him out when he goes to the door because he is doing so well with potty training but I don't wnat to encourage the barking.