I think this young bloke is trying to settle an argument with a school mate.
The answer is ...
1. Chooks can't fly all that well. They can fly a few dozen metres at best - if their wings haven't clipped, as many chook owners do to them. Their wings are clipped to stop them from flying over fences, which they can do.
2. GOULI is right - they'd hit the ground at about 120-150kmh, and you'd be picking up a dead chook, fer sure.