There is one major problem in trying to answer that - anthropomorphism.
I very well remember an interview with a life-long, long-in-the-tooth, farm vet' when free range suddenly grabbed people's imagination and the flocks started to grow - probably broilers at first. That has got to be 20+ yeras ago. For the first time in his professional life, he started to see lots of diseases and parasites in chickens that he had never seen before in his entire career.
In some sections of the Severn valley, free-range has now become so intensive that it is causing major and problematic eutrophication of the river - maybe 2 years back there were moves to reduce poultry numbers and there were certainly not going to be any more permits issued for new housing for new flocks.
Chickens are actually vile creatures unless kept in small groups - just as starters they eat each other to some greater or lesser degree.
Least stressed hens - probably singletons, or 2-3-4-5 birds in large pens with lots of things to occupy them.
Nearest that will happen commercially - very probably enriched colony cages. No predators, no disease, no parasites, warm, dry, no gales, food and water ad-lib, somewhere to dust bathe, a block to keep beaks and claws in trim, perches, a secluded laying area, just small groups of hens in each cage.
99% of people want cheap food............................... and recently, a lot of those NEED cheap food.