If it's a sick from the wild, it can probably fly away if it wanted to. You could always cut the flight feathers to make it tough to fly.. Not sure how to do that.
Although Guineas stent as pretty, I heard that they are very comical. Peacocks are gorgeous! Expensive though and they do better in groups. I live in a small town that is almost village like and somebody has a trio of peacocks that risk the streets freely. They sleep in trees and make a noise that sounds like a cat is being run over. Lol