Very interesting, I really liked that you measured while roaming around describing each spot. Thank you for doing that! Such varying heights and slopes. So - at least for your group there they really prefer the ground, and within that area, there are preferred areas. Stand-alone objects of some height, 4- 7-14 inches, and also tipped surfaces, are not conducive to mating, and everybody seems to know it? The hens know they are “safe” to run to (and also that narrow opening between two rocks)?
Today Shehnai pinned a pullet in a surprise move on her, and when she got away she immediately ran and jumped up to a low perch to shake, fluff and get her feathers right again, and it appeared to maybe avoid anything further too. I was thinking of you when I saw that!