How old are they? What breed?
Chickens are not very "brave", anything flying over heard freaks them out, it's instinctive (flying predator). If they're cooped, they should be safe & sleep. Mine are housed at night, free range during the day although spend a good time in my patio lounging. They got the routine down, will go to their house area about half hour before I close them in.
I've used Happy Hens freeze dried mealworms to train and entice them to do my bidding, the shake of the container or even sight will have them running. I've recently learned they also love rolled oats as a treat, cheaper too. Scrambled eggs another good treat when they molt, extra protein. They are easy to spoil...
Enjoy them...