First I would call Animal Control and have them come out and look at your birds and explain what your legal rights are in this situation. See what they will do. If it happens again, when the dog is there, call it to you, offer it food, whatever, then catch it and tie it up or put it in a crate. I would call Animal Control to come out and complain to them explaining the problem. They should take it away then call the owners to come get it. This will begin a paper trail to prepare for the next time it shows up, hurts/kills birds, and gives you the right to protect your livestock. It also lets your neighbors know that you are serious about keeping their dog from killing your birds and puts the responsibility in their hands for their pet. imho
Bubba, I agree that chaining a dog long term is cruel. It's entire yard should be fenced is such a way as to keep the dog from getting loose. But it is the owners responsibility to contain and control their pet. If they cannot, they should rehome the dog.