My chickens are about 4 weeks old now. They are in a spare bathroom, in a large box - about 3x3x3. They are flying out everywhere - won't stay in the box anymore. I was covering it with an old screen, but didn't know if they needed to "stretch their wings" or not. Should I continue to cover the box or should I let them "free range" in the bathroom and then give it a major cleaning in another few weeks. It's pretty poopy with them all over the place.