I am sure this is unhelpful and will annoy someone, but I just thought some might like to know:
Over the last few days I have seen a LOT of posts on hawks that state "must have been, i think it was, etc" a "falcon". Hawklike raptors come in 3 types... Accipitors (which are streamlined birds that eat other birds, often catching them in midflight) these are your Cooper's hawks and such which LOVE seeing chicken on the menu, buteos (chunkier birds that eat mostly ground dwelling critters) like the Redtail and will only rarely decide to dine on your coop dwellers, and true falcons which are the Peregrine, kestral (which your chickens could eat! LOL), and Merlin being common in US. If anyone has a true falcon preying on their birds... they should admire it... then call to have it removed or relocated.
As was stated in another thread... most Falconry associations can be contacted about a raptor of ANY sort (hawk, owl, whatever) and will relocate or trap birds that are decimating your flock. If the birds are just passing though... they may have some good ideas on making the "guests" unwelcome. And if you need to cull some stragly bantam roosters that are not worth plucking for dinner... they can become your best friend for a decent trade!