Thanks for all the info and opinions everyone. I tend to be a little overprotective and am glad to learn my concerns aren't unreasonable. I'm apprehensive of ANY dog roaming unleashed. Pits bulls in particular intimidate me based on all the stories of mauling by that breed in the news, seemingly, daily.

I've already explained to my son to never approach any dog without myself or my husband present. He LOVES animals, dogs in particular. He's at the age where dogs are all he thinks or talks about, he's 7 and has been asking for his own puppy for the last 6 months or so(we're planning to get another one after the holidays).

We're new to the neighborhood and initially I was thrilled to meet our neighbor with a son the same age as ours. The boys hit it off immediately. I'm disappointed to learn that I can't allow my son out of our backyard(much less to go to his friend's house) for fear of this roaming dog and the chained up dog worries me more. Like most of you, I see these as red flags, but I'm hesitant to broach the subject with our neighbor. We just bought this home and our children will very likely grow up together.