It sounds like she is not eating, her crop is empty, and she is passing yellow to green runny droppings. Hard to know what is going on exactly. It could be a reproductive disorder, possible coccidiosis, or any number of things. Have her eggshells been normal and hard? Some chickens may have a shell-less egg stuck or break inside, which can make them feel uncomfortable for a day or two. I would give her a few drops of Poultry NutriDrench is you have some. Other electrolytes will work as well. Try to offer some water up to her beak often. I would make a soft scrambled egg, and see if she would take some. Mushy chicken feed made wet with water would also be good to offer. Post some pictures of her droppings if you can.