Lighting is not needed from what I have seen. They go in and hop up onto the roosting bars when the sun is setting, now in the summer sometime between 4 and 6 PM.
I don't think it's necessary. We got a heat lamp and hung it right over a perch at the beginning of our poultry farming. What happened? Well, everyone moved to the sides; no one wanted to sit under the heat lamp. And the little chicks, up to two months old, sit under the mother's down in the nesting box first, and then for a while also up on the roosting bar.
We let our adult chickens roam free during the day. But we don't let them out earlier than 10 AM, after a fox came here one morning around seven and had a feast. Now, with the chickens out only about 10 AM - 5 PM, only a few chickens have been lost, and then to hawks. You notice the difference because the fox carries the prey home to the den, but the hawk can't carry a whole chicken; instead, it eats the thighs and neck clean and flies away when it's full, leaving the remains.