I have about 20 Iowa blues and rhode Island reds. I recently found one of the blues dead on it's perch.
It looked like it's cloaca had exploded. I think cloaca is the right term. There were two eggs on the floor nearby. My chickens rarely lay eggs on the floor but almost always in their nesting box. There were no signs of an invader. All the rest of the flock ok.
Did the blue try to pass 2 eggs at once?
Also, I have had problems with hawks. I have hung mylar tape and "scare" balloons. So far so good. Any other tips?