I agree that a dog would be ideal.
Our dog (not a LGD, but the kind of pet dog that lays around in the driveway all day and farts) needed to see a hawk get a duck before she caught on to the arial predator concept. Now, she is pretty diligent about watching the sky. So, do you have a lazy mutt?
Otherwise, a big rooster can be a big help. We don't lose egg birds to hawks anymore because they know when he (ruffles the rooster) signals to hide under the forest
canopy. Can you put a tree in each paddock, or set your
fence up around a tree?
The shade hoop Amos described sounds cheap and mobile, if not.
If you are in an open field, beware! We are adjacent to a dune, so warm updrafts mean torrents of predators spiral above on hot summer days. I sometimes wave them off, having heard that they have good memories, and hoping to instill a bit of "oh crap, human being!" along with the "mmmm, smells delicious" memory. They are much more afraid of the dog, FYI.
Good luck. There is nothing like death from above to strike fear in the heart of a poultry man.