Feathers on legs really make it hard to see a problem in pictures or videos. Sorry about your hen. Most of us do not have the luxury of a vet who could perform an xray on her leg and hip, but that would be great if you could see one. Xrays would probably be $150 plus an exam fee, if you found one familiar with chickens or birds. Sprains can take weeks to heal, and the same with broken bones.
She might have broken a bone, sprained her leg, or she could have a tendon or leg bone issue. How would you feel about letting the other broody raise the chicks, and confining her to a cage with food and water to force her to rest the leg? The chicks need to be able to go out and about to learn how to forage, but they also need to be protected from the other hens who may attact them if she is not around.
It might be better to just let her be with them and open the cage when she is ready to take them out for part of the day. I wish I had better advice, but you are probably a better judge on how to proceed. Good luck.
