Also wanted to add that we are in Ontario, Canada so winters are looooong and get very cold. There were lots of outbuildings they could shelter in though. And a large barn with other livestock.
Yes! When I was a kid, my mom kept a flock of mutt bantams and they were also 100% free range. She didn’t feed them at al (I’m sure they foraged kn the compost) and they roosted in trees. She told me she only ever lost one to a predator. We had 100 acres at that farm.