Well, I have figured out one reason why miss broody hates the cage. The 4 11 week olds have decided the top of the cage is perfect roosting space. They crap on her all night.
Chickens are just like children. The younger ones taking advantage when they can and picking on the big ones when they know they're safe.
Awwww! Zip tie some cardboard on top, and that'll stop the pooping issue.