Took me a day or two to figure out, but set up the critter cam to make sure. I have a dozen photos and the raven waits til a chicken comes out, then goes in. If a hen is in the coop, he won't go in. The chickens free range all day so the door stays open from dawn til dusk. I've read putting something like "caution" tape streamers at the door and little curtains on the nests? I won't kill the ravens, I've never seen a hawk here that wasn't being attacked by 3 or 4 ravens dive bombing it. Also I've heard hanging dead ravens nearby, I have some chicken feather pelts, you think that might work the same? I have no idea how many real eggs got taken, but they also took off with 3 ceramic fake eggs and 2 golf balls, the last one set up for the critter cam: