So sorry about your hen, but I think she may be in shock. You need to take her out and get some electrolyte and sugar water solution into her. If you have Gatorade use that. Or if you have something like nutridrench mix some with water and add a bit of sugar. Dip her beak in gently to get her to drink the solution or use a dropper to dribble a few drops on her beak so she will take them in. Try to get her to drink more than a few drops, though. Don’t put any directly in her beak otherwise you risk her aspirating. After she gets some of the solution in her, place her somewhere warm, dark and quiet to recover. She will be fine alone, it’ll be best, actually for the time being. You need to act fast, shock can kill quickly.
Does she have any injuries?