it looks respiratory (though i bet she has worms too). Can you describe the symptoms any further? ie, is there mucus by the nostrils, eye discharge, color etc etc. If it's just a cold it will clear up, but i don't think she would have stopped eating then. Other stuff will require medicine, if curable. Without it, and not eating, i think she will most likely die. You can try force feeding her some feed mixed with yogurt and vitamins and some gatorade to keep her going if she's battling through it. You should keep an eye on the other chickens because it may be infectious.