I'll let my chickens out whenever I get up, which is always before 8:00 AM depending on what time I need to be in at work. Regardless of how early it is when I open the door, they will not go out until it's light. I've opened at 5:00 AM before and watched to birds just stare at the opening until the sun came up.
As soon as they start losing light outside, they come in.
As soon as they start losing light outside, they come in.