Oh yeah, no. There are plenty of modern age chickens that do just fine being left to avoid predators themselves. Nearly all of my birds (excluding my ducks and the ones that need to stay confined) would have a fair chance most of the year I believe, so long as I made sure not to skimp on...
I think confinement in some places is the better choice. I have 4, probably 6 birds that would not last a season outside, probably not even a night due to flock dynamics, physical handicaps or in one case, just sheer lack of brain cells
Certain people might say that it's my fault for that...
Really, layer feed is the absolute lowest quality food out of the different stages offered other than scratch grains for chickens. It's designed to have just enough protien to keep small, egg machine birds alive in places where they aren't eating anything else. Almost anything else fed to them...