no problem. if its been happening for that long, yes, you should separate her. but keep her in a safe box neer the other chicks, so she can still hear them so she isnt lonely. try to get some fluids in her. its gonna sound weird, but try gatoraid until you can get some electrolites and minarals for her water from the feed store. is she pooping regularly? if not, gut some olive oil in her, it works well for constipation.