I've been giving her vitamins everyday and the food I give her is chick starter. I grind it up to powder then add water to make it just thick enough to go thru the tube. I keep checking the size of her crop. When it is an appropriate size I stop. She usually starts protesting close to being full. When her crop is empty I feed her again. I give her water before I feed her. I give her about a table spoon of water before I give the food. She had lost some weight by the time I discovered something was wrong. She was always sitting somewhere when I went out to feed and water. I moved her out of the pen she was in because I had a feeling somebody in that pen wasn't being very nice to her. I never witnessed any abuse but by the way she acted I thought that was the case. When I set her down in the trough I have in the carport room where she could be warmer and away from the other chickens she wobbled and went down on her side. I brought her in and sat her on the floor and she was walking backwards and in a circle. I was told it sounded like a brain injury. So I started treating her for that. Then as advice came in on what it could be I treated her. We had a set back when I gave her corrid but lesson learned on that.
So what I"m doing for her now and it seems to be working is tube feeding her and giving her vitamins every day. She is now eating and drinking a little on her own but I still make sure she gets enough to eat by tube feeding. She now has food and water available to her in her cage. She is in the living room so I can watch her and she has been doing pretty good. She gets around the cage but not the regular way by walking. She flaps her wings to get where she wants to go.
I am going through the same thing right now with an 11 week old lavender Silkie cockerel. He started out with his head between his legs, forehead on the ground and could only walk backwards. I had to hold his head up and force feed him "Kaytee" Exact dry hand feeding formula mixed with hard boiled egg yoke. The egg yoke really makes them want to eat! I also added vitamin E (1 capsule cut and squirted in the food daily) and a pinch of yeast (B vitamins) daily to the Kaytee. I also give him a few drops of Polyvisol baby vitamins daily. It has been about 5 days and he can hold his head up, is taking some steps forward and eating on his own. I still have to make him drink by dribbling water into the side of his mouth with a syringe. He might be drinking a little on his own but I have not seen him so I will continue to make him drink. I am so happy he is going to make it! He is the sweetest boy!
Good luck with your girl!