Ladies fist is fairly large for a hen. I would find this acceptable just before bed from a hen who gorged all day and otherwise healthy. I would guess this is your problem, since she has green stools (indicating no food passage), her crop is not moving food. I am going to go with the person who recommended the massage. Try dipping some small bits of bread in olive oil and get her to eat it, then massage. Please keep us posted. And yes, keep her off food for tonight and just encourage fluids. IMO, acv is not necessary, but a good vitamin & electolyte mix is essential right now in her water.