I am sorry about your hen. Generally when they get to this point of not eating or drinking, and they lay asleep unless disturbed, unfortunately this is a sign of dying. I would bring her inside and get her under heat. Sick and dying birds get very cold. Keep her as comfortable as possible and hope for the best. But it doesn't sound good.
You can also post this in the emergency section for more insight...
Good luck with your poultry raising adventures, and I hope you find everything you need to know. Don't forget to take a look at BYC's very useful learning center (If you haven't already)! The learning center as well as the forum should answer your questions! There is always something new to learn! Glad to have you here! See you around with the flock. Try posting this in the emergencies forum.