Also, regarding the aggressiveness, it looks like she's going to lay any minute, so she's probably asserting herself as queen bee in the hive. I would imagine if space is adequate, she'll stop being as aggressive when the others bow down to her satisfaction, then the pecking order will be established. If you've had her separated for any length of time beyond a few days, it may have just done the trick, because that would put her at the bottom of the ladder when you re-introduce her. Offer lots of treats, like a whole melon cut into bits and scattered all over, when you put her back, so they don't focus on beating her up
Good luck!