Chickens penned 100% of the time also die and can face injuries. Free ranging gives best quality if lufe, imo.If you cannot bear the idea of a chicken dying or being killed, it is best you never free range. There are some losses.
I try to limit my losses by locking them up every night and not letting them out until it has been light for a couple hours.
I want my chickens to live the life I would like, as a chicken. I know I would be safest never leaving my house, never driving, never seeing other people. Life would stink, but would be safe.
The chickens in my idea are the same. I could keep them locked in a closed fence and coop, and they would live to the ripe old age of 3-4. OR I can let them out. Keep them as safe as possible and allow them to live a good life. That is why I free range. I would rather live a good life than a long life.
Wow, I sound like a philosopher!