The poop also is indicative of a hen who is not eating. It's a tough call, but I might try force feeding her a little water fortified with yogurt and/or honey just to get some calories and hydration in her. I agree, it is not a long term solution, but if she continues to refuse water, I would try it. A little energy might jumpstart her natural instincts.
I had one hen in shock due to a predator attack who had ceased eating and drinking. I read that a dehydrated bird could, ironically, lose interest in drinking and eating and go rapidly downhill. After forcing liquids and some food into her for a couple of days, she rebounded, and is now fine.
If you go this route, just be careful when getting water into her. It is imperative you get it down the esophagus so you don't get it into her lungs and drown her. I used a syringe and made absolutely sure it was down the right "hatch" so to speak before gently emptying it.