Araucana Nest
FreeBird
I'm so sorry. My only experience with losing multiples at one go was with a fox. A fox will take your whole flock in one day for the sport of the kill. If there are homes going up around you, they're being driven out of their "homes" and will begin to look for new dining spots. Foxes are very difficult to catch. Best to lock up your flocks until it decides to move out.