Very excellent science, centrarchid, love it! And a few great laughs, too! Someone said something about older birds not flying anymore... I know this to not be true, at least in my flock. Also with the egg laying thing... My best flier, Hedwig, finally started laying and, although she is just getting started, hasn't slowed down in the flight department at all yet. I have noticed that some will fly for fun (i know there's no food left in the coop but i feel like going back in anyway! Says ginormous BA roo) while others just can't be bothered. I don't recall seeing all these varied personalities when I had chickens growing up but seeing it now that I have them again is just so fascinating!