Good relations with neighbors is important and the dog didn't cause a lot of damage this time. I would talk to the neighbor and explain what happened. I am not saying threaten them, but let them know that if the dog is on your property and attacks your birds/livestock at some point in the future you will be forced to take action. Don't be rude about it, but be firm. They may be reckless owners or this may have been a one time deal. Feuding with neighbors is a huge headache, so just remain calm and all should be well.