If you are taking anything that thins your blood the risk is way higher, so factor that in, please.
Right, but now we do. We already knew from your previous posts this is an issue, but repeat hits to your head, like on the regular? Not good. And I have thoughts, of course.

Seriously consider at least some kind of warning object - like hanging some hippie beads or something that hits your head before the damaging beam does.
I wonder if there isn't another way to support the coop roof, such as a metal cross-piece that requires much less bulk to be strong. Or an exterior beam that suspends the roof structure. I know you have glass or plastic windows up there? I'll think on this.
You could add a knee wall to your existing structure and raise the roof. Is that tree still in a position that you would have to have the roof that low if you were building it today?