I suggest closing off any windows through which outside light could enter the coop. Get some black-out blinds if you have to. Feed them late then turn off the lights. When they’re on their roosts, pull the blinds or close the shutters. Try to exclude all light but without closing off needed ventilation. You’ll have to be creative, I’m sure. Maybe relocating the motion light would help, depending on where it is in relation to the coop and any possible light leaks. You ought to move it occasionally if you can, anyway, so predators don’t get used to it.
