Wait you said she was the one being aggressive... are you sure the blood was hers? Keep her separated for a few days and when you reintroduce her put her on the roost at night when it's dark. That's your best bet. There will be some scuffles the next day and they reform a pecking order so don't be too quick to step in and help, pecking order keeps peace in the barnyard unless someone is being visibly harmed.
Yes it was her picking on the others.. they were just trying to walk away from her and it didn't seem serious or I would have stayed to see what was going on. None of the others have any marks at all, I even looked at their beaks for blood or feathers to try and figure out who was the perpetrator but nothing. There was splattered blood in quite a few places in the backyard and in the coop. She doesn't seem happy at all to be in the garage.