try to give her some water with a syringe to wash the mucus then try to put some food in her mouth. I was putting cracked corn and wheat one by one or I mixed chicken feed with water and gave it with a small spoon followed by giving some more water. it is even better if you put some honey in water. she must eat and drink! and put her inside where is warmer. she will need some antibiotics but you should consult a vet.
good luck!
**If her crop is full** this morning but she is not eating, DO NOT force feed anything! Hydration is what is important!