We live semi-rural and a couple years ago some new neighbors from over a mile away let their dogs out and it killed one of our chickens. When I found out who it was and confronted them. They were surprised that they couldn’t just let them roam.
I have lived in the country (outside of a big city) for much of my life, and in my experience nobody keeps their dogs penned up. I can name five of my neighbors who let their dogs roam.
From my experience, in the countryside it is normal to let dogs roam. Of course it's also normal to expect them to get shot if they get into someone else's chickens.
Usually they will be warned by the neighbor before they shoot them, and sometimes the neighbor will say "go ahead and shoot them if they get into your chickens."