Did you give her the activated charcoal? If not do so.
Then try what I just gave my recovering sick hen. Boil up some rice. You will probably need to hit the health food grocery for keifer, millet, flax seed, and millet and tofu. It happens to be stuff I always have, but it's well worth your time to buy it. A change of menu can really make a difference for a sick chicken. Right now, just crack a raw egg over the hot rice. This may interest her in eating.
For tubing, I use raw egg, water, Nutri-drench, some uncooked baby cereal or Cream of Wheat to make a semi-liquid concoction. Be sure it's warmed to body temp. Make about half a cup.
I wrap the patient in a bath towel to confine wings. I wrap my arm around her and pry open her beak. Then, holding the beak open, slide the tube into the chicken's right side of her beak, going slightly under the side of the tongue and then down into the crop all the way. Close the beak on the tube.
Fill the syringe and insert it in the tube. Force the food into the tube slowly. Refill the syringe and repeat until the crop is full.
If the tube pops out, rewrap the hen and reinsert the tube, and proceed again.
This shows where the tube goes. This shows a syringe, but the tube is the same.