I never thought of this. When a storm comes my chickens hide under shelter, they don't go in the coop. I can see how this could be a problem. I live in FL, and when we get a storm...... whew boy it can get dark. Probably due to being right on the Gulf of Mexico.I had a photocell on my door and a thunderstorm came up and the door closed! If I had to use a commercial door IMHO a timer is better because you can set it to close at dusk and every chicken will be in by then.
JT
Any thanks @jthornton I never thought of this scenario.
How often has this happened to you?