Interestingly enough, not all the birds with features survived ~ only "wading birds" with breast bones. The other types died out.
BTW, you can think it's humanity controling the chicken, but you'd be wrong.
Um. No. Wrong on the Oxygen levels:
Where is the evidence of roasted dinosaurs? (Hint: there isn't any).
It is a mutually beneficial relationship. The productive ones can breed (and we encourage this), and we eat most of them. We give them all of the reproductive success that they need to produce more chickens, and then we eat most of them. They reproduce more in captivity, and have a much larger population, than they ever would in the wild - even though we eat most of them.
Are there wild chickens? Not being facetious, just curious. I don't mean chicken-like birds, I mean wild chickens.