How to get hawk away from backyard?!?

[ChickenMath101]

We lost 5 chicks in one day to a hungry hawk family this spring. I was HORRIFIED. I expected a loss here and there, but realizing they would kill them all within a week sobered me into an immediate solution. We used neon green braided fishing twine-not the plastic stuff, it's like cotton or nylon rope? Anyway, we stretched across our entire chicken pen (it's at least 1/2 acre, so quite the job) and haven't had a single loss. The hawks have been seen sitting in trees, staring at their lunch. They've been seen hovering over the top of the line, furiously flapping while they try to figure out how to grab their snack. But they are just not going to go in between that 18" thread and get stuck. No way, no how. (We do have 4' 1" chicken wire stretched around the perimeter, which protects them somewhat from the four legged critters. But the twine has been extremely effective against the hawks.)