Hi, welcome to the forum! Glad you joined!
I have no idea what country you are in, what predators you might have, or what climate you are dealing with. All of these could be important.
I grew up on a farm in the hills and ridges of East Tennessee. Dad had a flock that free ranged and fed itself year around, though on days with snow on the ground we'd toss some shelled corn (maize) on the ground for them. Most slept in a henhouse that was locked at night but a few slept in trees.
They were basically game chickens. I would not be surprised if they were descendants (in part) from the chickens the pioneers brought to the area in the 1700's, but Dad brought in some other dual purpose chickens to improve the stock. I remember New Hampshire and Dominique but these quickly interbred with the games. And they were raised with the games from 3 weeks of age. Just left to free range.
Every year broody hens would hatch and raise chicks with the flock. A snake might get a chick occasionally but it was really rare. Most hens raised every chick they hatched.
We were in the country, pastureland and woodlands all around. From the time I can remember until I grew up and left, we had two predator attacks. One time a dog was killing the chickens. Dad was at work but Mom's brother was visiting. My uncle shot the dog. He was raised in the country also. In the other attack a fox was ambushing a chicken every morning shortly after sunrise. I saw him one morning when I was going down to feed and water the hogs when Dad was milking the cow. Dad ambushed him the nest morning. Both of these were during the daytime.
Those were the only two major predator attacks I remember from growing up with free ranging chickens where some slept in trees. It is possible we lost a random chicken to a hawk, owl, fox, dog, raccoon, or something else but I don't remember it happening.
There are a lot of comments on this forum about free ranging chickens, many of them from people that have no experience themselves. You may go years in between predator attacks. You may be wiped out about as soon as you try it. You just don't get guarantees when you deal with animals and their behaviors.
Good luck!