Take a tub of warm water. Not hot, not cold, but warm and nice to the touch. Gently ease her in, and let her relax. It sounds crazy, but most chickens actually relax and even fall asleep in it. If you have Epsom salts, use them in the water. If not, just relaxing in the warm water may let the...
It is possible that she may be egg bound. To check, wrap her up in a towel, so she doesn't fight you. Put on a glove and put a small amount of Vaseline on it and check her vent for an egg. Yeah, it's gross, but it will help you determine if she is egg bound. If you do feel an egg do an Epsom...