My Americana bantams thrive through all but. twenty to below, but before that are completely self sufficient, laying daily, and just this summer got most conditioned to ropst n lay in coop, n allow locking up at night. I've lost two to gf's cat that was "taken care of), n aside from that had no pred trouble, n even get eggs down below zero (you have to supply some warm water a day, was told n do just cause can't hurt hopefully ). I think banty etc, better choice that layer dual heavy meat utlity strains for free ranging, as i get med egg every day each except in heat waves for days occasionally.
my chooks have flying swift running skills etc, pretty gamey, n have dogs scovy ducks guinea n good cats that all sound alarms n each attack alone and together anything that comes on unfenced property in hills of east TN. had two bears n a panther being worst ones dogs got hold of n tried to kill before got them off with cane pole (pretty bad when your having to save preds that your dogs otherwise wear down n rip apart slow). ps my birds also good meat, n just mcmurray hatchery stock got from free ranger farmer that left them be free etc n these just what wasn't taken by preds or disease in guessing just got lucky or adpted back to semi feral state.