If this happened to my hen, I would just get her drinking often, mix some watery feed and a little egg, and give her some mineral oil in the food, or chilled coconut oil to peck at. Tube feed her fluids if she is not taking them. If she won’t eat, get her pecking at the chilled coconut oil about 2 tsp twice a day. Keep her separated so that you can see her droppings. How does her crop feel? Check it first thing in the morning to see if it is emptying. Let us know how she gets along.