[medved]

One thing I forgot to mention which should be obvious is that the escaped chicken is working from a gigantic numerical base while the velociraptor bird-wannabe is working from a miniscule base. The odds would favor the chicken over the wannabe by orders of magnitude.

The reason the escaped chicken can't regain decent flight is fairly simple. He started out in life as a wild fowl weighing a pound or two or three and then was bred into a domestic bird which was heavier than that without his wings getting any larger in the process. Similarly, a dinosaur trying to evolve into a bird would not have any way of knowing how big his wings needed to be at the end of the process and there's no reason to think he'd do any better.

[RonF]

Actually, the escaped chicken is working from a miniscule base. And because her wings have been clipped, and she's too damn fat, and she's been comparatively immobilized to keep her fat and keep her laying eggs, she goes from miniscule to zero pretty quickly. But the raccoons and foxes get fat.