Good morning, I have rope crossed all over their outdoor pen area in a random pattern for when they are locked in the extremly large pen if I am not home. I have also used just a few strands of rope in a larger free range area and never had an issue with flying predators. The area I do not have ropes strung across is where I've lost a bird every great once in a while.
The idea of the ropes is to deter their natural swooping down hunting style in an open area. The hawks fly over and see the rope and move onto easier hunting in more open areas. I see them all the time. I am not saying it's 100% effective and will work for everyone all the time, but so far its worked here and gives me a little piece of mind and keeps my flock happy and able to free range when I am home.