Omg, this story touched me particularly. One of our dog jacky ate the neighbours chicken last month, and we often keep it with a chain next to a tree, your story broke my heart a little... He is my best friend though, but he needs to understand that he can't run around kill neighbours chicken, they have shotguns!
We even bought an electric collar, with a perimeter that he has to respect, but I was too scared to hurt him, so I took it off.
Now we will build a fence, because he will run away again, and eat more chicken 😄