I had a small group of six that learned to sleep in the tree just before the new coop was done, I'd trick them with treats to get them early and into the coop. One night I could only catch one...well, that was the night of the owl attack, it took the biggest and the rest came screaming down the hill, never to roost there again, and always the first in the coop after that. Hard way to learn. Fortunately the owl took the young roo....but still.