Aerial predators can also be a problem. Hawks will hunt during the day, and owls hunt at night. While we don't cover our large pastures for the adult birds (knock on wood, we haven't had a problem) we do have a cover for the outside pen attached to the nursery. We allow the young poults to go out of the nursery at 3 weeks old, and move them back inside in the evening. We have had a coopers hawk sitting on top trying to figure out how he was going to get a young poult. In the adult pasture, we reseed the pasture in the spring with a variety of plants like millet, oat, rye, and sunflower. the tall plants provide shade from the heat, visual protection from aerial predators, as well as house bugs for them to eat. They soon eat most of the vegetation, and by then, are too big for a hawk or owl.
Dogs can be a deterrent, but can also be the predator. We researched breeds and determined a doberman was what we wanted as a predator deterrent. They are very smart, loyal, and friendly. Still, Lexi definitely knows the difference between a friend and foe, and is not afraid to drive off unwelcome visitors.