We have a ton of raptors out here- we've seen 8 bald eagles at a time; also, eagles, red-tailed hawks, marsh hawks, and ospreys all sharing the same patch of sky over our house (and over our chickens and ducks!). I know some of those species are territorial, but it's a big marsh we look out at, with a salt water bay nearby, and I guess there's enough habitat and food for them all.
I hesitate to share this, for fear of jinxing its success; but, for the year I've had chickens (14) and almost 2 years with 5 ducks, I've used monofilament (fishing line) strung around the lawn between 4' bamboo or fiberglass posts. I move them around when I mow the lawn, and I think that the fact that they're hard to see- as opposed to netting the whole area- and not always in the same place, confuses the raptors. At any rate, haven't had any attacks (knock wood!) in an area where lots of people do lose birds to eagles, in particular. (A friend lost all of her ducks to an eagle who ducked in through a small gap in the bird netting over their run, repeatedly- they saw the eagle do this, unfortunately on its last fly-in.)
We have electric poultry netting around the perimeter of our large lawn; I let the birds out in the AM and put them in at night, so they're out there all day- and believe me, the raptors know that they are there! (Sometimes, neighbors call us to warn us that the eagles are scoping out our birds!) There are not any trees nearby for the raptors to sit in and ponder, which might help.
My husband's not so fond of this method when he encounters a newly-moved fishing line, in the dark; but so far it's working to protect the chicks and ducks.
Anyone else tried this?