Bob I just saw your post about answering your own chicken's questions....here we are chatting about you and your gang. But apologies anyway.
I don't think
@BY Bob 's cameras are on 24/7, and he has a better idea about this, but I think the one hen who needs to eat gets up regardless. Maybe with the motion the camera comes on, if it's set to do that, and it helps her. But - mostly, I think she knows where to go, even in the pitch dark. She needs to eat so she's trained herself to do it blindly (blind people do this). But also it's likely there's some light - including IR light - from the moon, unless it's a new moon, and the neighborhood's outside lights and streetlights provide ambient light too.