So sorry to hear. I couldn't imagine all the birds gone.
I came home 2 weeks ago to a dog still in our run. The dog got in but could't get out. Still cant figure how it happened. Killed 2 hens and the rest somehow made it into the hen house where the dog didn't venture. It was middle of the day, urban town, and the neighbor was watching or I would've choked the dog the death. My emotions were very high at that time. I paraded the dog around the neighborhood until I found the owner. Told him his dog wouldn't make it out of my yard next time. I called animal control and they say its a civil matter. "IF" it ever happens again I will do what it takes to protect my girls. I still cant get over the response I got from the owner when I told him to look at the blood still on the fur around its mouth. Shrugs shoulders and says "sorry".
I would send him a bill for replacement cost for the chickens. Maybe next time he will keep the dog home. Sorry about your girls:-(