If you have a good magnet you can put on a string or a stick, lower that down into her throat & get the bolt out! Or try to get it from the outside of her throat with a very strong magnet. Otherwise she may die. Slowly. Do this now if you can.
Do any of your chickens suddenly stick to a magnetized surface, now?? That's the one! I think it will be okay - a bolt could either pass or stay in the gizzard as "grinding material." I'd worry more about staples, nails, things with sharp points. I really do totally understand your concern. It just struck me funny for a second there... forgive me.
