Very interesting. My Grandma raised broilers on contract when I was little, um, in the 70's. Very small by today's standards, just two small buildings (compared to what I see in Georgia today). It was extra money on the farm. She gathered a lot of eggs too, so I don't know, maybe it was something else than today's broilers. They were white, and back then I was clueless. Or she had separate flocks? Anyway, she insisted on lower numbers than the company said she could have so they had more room. But it certainly was never so spotless.
Back to the video. Yes, the farmer will do everything possible for healthy birds, and to produce something that's going to be sold. Very clean birds in those recycling shots. So, "free range" simply means, no cage, but still packed inside?
I have read some research on diseases spread by wild bird contact. It is a valid point that it would be harder to isolate a backyard flock, but opinion seems to be the backyard flock is healthier due to the constant exposure and all, and in itself more isolated from other poultry populations.
I have been to egg production places, some only a mile away here. They look nothing like this! More like the animal rights nightmare. Gah! I'm just very, very thankful I am still allowed to raise my own. My birds are healthy, get real sunshine, etc.