Sorry for your loss.
Make sure that all of your dog owning neighbors are aware that you have chickens and that there was a dog attack. Hopefully, whoever owns the culprit may keep them in. A long time ago we gave all of our neighbors a warning. It worked for everybody but one. That particualr neighbor has a court date next month his dog crimes. If you don't free range your birds, you could reenforce your run, but a determined dog can get through quite a bit. Once we had a rabbit cage made of some pretty substantial stuff. A dog (different dog - same stupid owner) actually pawed and chewed until it got through. I have a friend with a border collie that actually severely damaged her teeth gnawing through a fence. An electric wire may be helpful. A shot gun even more helpful. I am at the point of zero tolerance. Dogs roaming on my property will be dead dogs. Unfortunately, it is not possible to keep an armed patrol on watch 24/7.
If you are friendly and well acquainted with your neighbors, call them and tell them about the dog attack. If you are not, send a letter to them. It can be friendly and civil. This is how I put it to my neighbors many years ago:
Dear Neighbors,
I just wanted to let you know that if you hear a shotgun being fired do not be alarmed. We have recently purchased a gun and will be practicing with it. Unfortunately, roaming dogs have been entering our property and harrassing/killing the livestock. We cannot afford to lose our animals to these dogs. All roaming dogs, regardless of breed or ownership, on our property will be shot. We just wanted to inform you that there will be some noise from the target practice.
Sincerely,
Me
This tactic worked with every neighbor but one. They moved in after this letter, but they were given plenty of warning. Warn your neighbors, and take action if they do not heed.
BTW I am looking forward to seeing pictures of the new babies.