I loose a small number of birds annually to hawks.  Several hawk species are present (Red-tailed, Coopers, Red-shouldered, Broadwinged, Sharp-shinned, and if want to call them hawks-the American kestrel).  I can see them at any hour during day.  Only the first two species have taken any of my birds and their take is influenced by many things.  Coopers take almost exclusively juveniles and chicks, and almost without exception those losses involve individuals that are not under protection of harem (hen(s) and rooster).  Adults of the harems are very effective at repelling even adult female Coopers hawks.  Red-tails are a different matter and will take adult chickens, even the toughest gamecock, if the chicken cannot get to cover that denies hawk advantage of flight.  Within cover, even then hungriest red-tail is taking a risk from attack by rooster unless latter is in green feathers or not part of a breeding group.  For some reason a harem leader will attack while the same bird if not a harem leader will not take on a hawk.  Hormones involved I think.  Most of time hawk either misses or is repelled but sometimes he does get his dinner.  The only time hawks do not seem to be hunting yet flying about is at twilight.  Owls (great-horned) are my concern at twilight.  My birds are strong fliers so are at greatest risks from foxes and coyotes which can get much closer when chickens can not see as well at dawn.  Having my birds come off roost too early wrenches my gut owing to such varmints that otherwise have a hard time catching anything other than juveniles.  Racoons and opposoms are not a threat to mobile chickens during daylight.  I have had both as pets and neither has the run down skills needed to catch an adult chicken that has option to run/fly away.
Dog greatly reduces even attempts by the chicken eaters.  Only persistant predator with dog has been red fox and it has come very close to getting mauled by my small but very fast bird dog.  The same fox could make kills regularly if  a larger amd slower typical livestock guarding dog was tasked with same.