Depends on what's hunting (location here is wooded). Merlins, Kestrels (and their ilk) along with Sharp Shinned are small (relatively speaking) and, more often than not, exhibit low angles of attack, and when they do stoop, they spend more time low above the target before the dive. Large Breed chooks with a bit of cover will cut down on any losses from these "bantam contenders". Saw a Merlin as it caromed from the flank of a BSL hen. Hen noticed the raptor as it winged away - earning only a growl. Have a resident Red Shouldered Hawk (five years, now) that wings above runs, but has never bothered with the chooks/turks (more on that in a moment). Red Tails arrive with the wind, but they make their examinations of runs from height, they'll observe from roosts in trees surrounding clearing around house, but have never gone into that "quick float" to zero target before torpedoing dinner"(stooping through tangles of branches is not ideal - and what additional "interference" I can provide I will).
Turkey hens are best (one of our Mottled's flew out of run to harass the Red Shouldered - hen had apparently made several circuits of the hawk on the stump - I only caught the end of the "stand-off" - hawk "squirts from disgust" and flies off): https://www.youtube.com/watch?v=X4DdvQ84MO4
Anyway, neighbors up the road have lost chooks, in their run, to Red Tails (over past decade), we haven't. Can I say that the CD's & pin wheels didn't account, in some fashion, to the variance in predation? No.