From the folks in my area that I spoke to about keeping turkeys it was owls rather than hawks that were the problem because of the problems of getting turkeys to go into a coop at night.
If a hawk is hungry enough he'll even go after deer! There's video on youtube of a hawk taking down a deer, it's actually pretty cool. My turkey free ranges all day everyday from 6 am to 8 pm with our ducks, she goes right in the pen and roosts at dusk! She's very smart, and loveable cuz when we get home she runs to us! Well my husband brings her fresh fruits & veges from work everyday so that may have a little to do with it, lol.
But back on subject, we have 4 regular red tails, & they even have a nest about a football fields length away from our house. Owl we have too, but never no problems from either.
Never seen a red tail go after a full grown turkey, they will try to take poults in the wild if they stray from the mother..
Heck they sit here in the trees right above and watch our orps freerange and don't dare take a poke at them, i believe they are watching for chicks or trying to single out small birds, but good luck with that...
i have lost 2 araucana hens to hawks in the last 7 years, but they could never pick them up and fly away with them, they started eating on them on the ground, cause when i chased them they tried to carry the hens off, but couldnt...
also i have seen them bounce off my pheasant flight pens on occasions..lol
they hit it once and never try again..
biggest threat is 4 legged critters on full grown turkeys and any birds here..but of course im a threat to the 4 legged critters here and keep them in check 24-7-365....
first let me explain that i wanted to become a falconer, so i have done some studying on the red-tail hawk
a large hawk will weight about 36 oz or 3 pounds and a hawk can not fly off with anything that weights more the it does.
what a hawk will do with prey bigger the it is fly in attack and kill its prey then pull it into the bushes so it can eat in peace.
OK that is some of my knowledge on hawks, now for a life experience.
i was hunting in a tree stand and had some turkey decoys out in front of me as i sat there waiting i hear something fly over head as i look around to see what it is i see a red tail hawk swooping in at my decoys, it turn back up after it got about 15 feet from the decoys i guess it realized they were fake
i dont know if it would have continued on if the decoys would have been real but it acted like it