Ok, new situation has come up with my flock of 12 chickens. We started letting the chickes free range during the days since the weather was getting much nicer. We noticed less and less eggs in the nesting boxes; found a couple in the run recently. Today we found a nest of them outside the run in a small nest of leaves under a large rock in the woods, near their coop. Why wouldn't they return to the nesting boxes where they always had them before? How can I stop this from happening, without having to keep them from free ranging? Any suggestions would be great!