malkared,
So sad to read about Belle and her chick. Something like that happened to me after letting my Jersey Giant hatch in the coop with the others. Let me just say it turned out very bad....
If you cant move them to a separate broody pen then take some wire that the chicks cant get thru and surround the broody and eggs so the others cannot get to them. I would put a sheet over the top to give them privacy. I have had chicks just disappear in the past before I started doing this. Some people have had luck in letting their hens brood with the others but I havent.
Dont give up. Just look at this as a learning experience. pdriverman and fisherlady have some excellent advice on this matter. They have a lot of experience. Let us know how the others are doing.