Is she caged within the coop or run with the others? That would be better for her happiness. If you a let her out with them some daily, and pull up the food so that she doesn’t gorge, she would stay a part of the flock. You can make a homemade crop bra by using tube socks. There are all sorts of ideas. If anyone around you can sew, that is another option. Also don’t forget to try the yeast cream orally.