My predator attack probably won't be my last. The birds simply love free ranging & I would need to build a much larger run to keep them in all the time! In fact, some of the girls & 1 of the roosters are out in the woods out back right now. We have the same issues with the "ground" predators..fortunately those usually come out when it's dark & the girls are in.
And, you are right, it is virtually impossible to completely ensure they're safety no matter what ya do!
My neighbor & I share about 12 acres; there's 100+ acres of woods behind me, then we're surrounded by corn fields & cows.
So far, my rooster, Bigboy, has truly done a fantastic job warning the girls...and, I am so happy that one of my 20 week old cockerels just gave the warning sound a few minutes ago when something flew overhead (think it was a bluejay)...girls ran under the deck (have a whole house wrap around deck).
I know a lot of folks can't have roosters...because other than keeping them in a safe run, they are GREAT at protecting (as long they don't pull a Rana & wander off alone

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I gave my other rooster , Blackie, to a friend who had lost 3 to hawks last year...since she got him, no issues.