None of that is evidence.
You think chickens should be outside - that's fine. The fact that you believe something doesn't make it an incontrovertible fact.
Why do we even need evidence? Buildings are not in nature, they do not just spring up out of the ground. Animals do not live in buildings. They just do not. Buildings are boxes that humans make to be comfortable in. Sure, you can lock them in there and not let them out, it is perfectly legal and no one can stop you, but it is not natural in the slightest. Domestic chickens are pretty different than their true ancestors, but they have not yet been so mutilated that they lack feelings and desires and the want to forage. Anything that breathes and has energy lives in the outdoors, it is the true home to everything. A building is an artificial nest that humans make. If they want to live in it for the most of the day and breathe in stale air with artificial lights, no one is going to stop them. But why lock other creatures in their, too?
Where is your evidence that all chickens want to be inside all of the time? And no, I do not mean university propaganda littered with claims of evil ground cooties and airborne fairies that kill all the delicate chickens instantly; claims of better health in stale, processed commercial "feeds" and protection from cruel, murderous wind, rain, and red-eyed predators. I mean REAL evidence - every chicken in the world telling you they love the indoors and that they never want to see the inside again.
They are not going to tell you. They cannot speak English, or any other human language. The only way for us to tell is to see how happy they are outside - scratching and running and jumping and basking. We know they are happy because they choose to go out on their own, and show typical signs of distress (yelling, pacing, running their faces against fencing) when penned up.