The buzzards here fly low and it scares the mess out of my flock and they run for cover they never attack flock since they like dead things but it has trained my ducks to poop n get whenever they spot something overhead even airplanes. Remember hawks stake out their victims sometimes days ahead of time so change up your routine sometimes. We have the occasion hawk in the summer but come jan-feb every single day these things stalk us. Hawks generally do not kill something larger than themselves but will become desperate in winter a cover would be a great idea b/c they can fly in runs as well. Oh you could convince a flock of crows to move in lol they hate hawks more than me. Just be careful study your environment and enjoy your future ducks btw I wouldn't let them out unsupervised till they have age and weight on them.