if a hawk will attack a chicken depends on 5 factors, Size of pray compared to hawk, How hungry is the hawk, Approach the hawk has Available, species of hawk, age of hawk,
now let me explain this to you. normally 2 most diurnal Birds of prey that will attack chickens or most Fowl is RedTail hawk and Coopers Hawk others do attack just less common,
Size of Pray Compared to hawk, a Coopers hawk wont even attempt a larger chicken but will take on smaller breeds(Depending on how hungry they are), Redtails will try almost any size Chicken But there Slow so you can Make there approach less suitable which will give your chickens a greater chance of escape and evade.
How hungry is the hawk, a starving hawk will go suicidal on a bird 10x bigger then them, 75 80% of first year hawks die in the first year due to starvation, Man, Larger hawks, Disease (non are human contagious) and even killed by pray will we will get in to that on age of hawk , During the summer when pray is Very abundant your chance of loseing a chicken to a hawk decreases
Greatly, but around Oct to Nov during migration and when most pray left has got smarter birds get hungry and they will try stuff they normally would not which lead to lost fowl.
Approach the hawk has available, most hawks wont attempts a long flight (note im not Referring Falcons Which will not normally attempt chickens) Referring to Buteos and Accipiters
Approach is the path and the cover the hawk has to reach the pray before its alerted, Long flights give reduced chance of success for the hawk and they don't want to waste energy on missed flights so they wont attempt 90% of the time all comes back to hunger, if your free ranging your chickens keep them away from wood lines, or a solid wall over 4' with no sight through it,lone standing trees in a field these tend to hold redtails alot waiting on rabbits and mice your lose more to goshawks and coopers close to wood lines, Low cover no more then 2 1/2 feet tall like bushes shrubs or hides for them to take cover yet dosnt impair the sight of a incoming hawk. if your birds get sight and start running there is a greater chance of them surviving the hawk will have a less chance of geting a good hold on a running chicken rather then a stationery one,
species of hawk, there are about 208 species of hawks in the world but only about 7 types will attempt a chicken (not including Eagles as i do not have much experience with them) these include Coopers, Redtail, Furreginous, Redshoulder hawk(smaller chickens), Goshawk (only if you live up north or in the mountains), Harris Hawk(mainly confined To Texas newmexico), Great Horned owl,
Age of bird, this is probably the biggest defining factor if its a Adult it normally would not attempt a chicken for hawks they really are not that nutritious for hawks, they perfer darker meat birds like ducks, but for a first year hawk they do not know better its like a teenager they think they can take on more then they can most will attempt once get hurt by the chicken or miss to many times and give up but they do get lucky those are the ones you lose the reality is your chickens probably get attacked daily but hawks are only 5% successful on there chases
if you pay attention to the approach that hawks might have on your property and adjust it you can Reduce number of attacks and lost fowl provide low cover for chickens to allow them to evade
and hide Hope this helps