help my Sick older girl

[wmroth]

I have an older hen. She is about 3 years old. A couple days ago, when I let the girls out to free range, I noticed that she seemed to go and hide. When I picked her up I saw that her comb was very droopy, a sign of dehydration. I put fresh food and water by her and she drank but would not eat. Later I felt her crop and it was water filled. Thinking she may have sour crop or a blockage, I rubbed her crop and she throw up a large amount of water. I tried feeding her yogurt and molasses with water. I rubbed her crop every hour and kept her isolated. By the end of the day there was little change. She was have difficulty walking. She is weak and stiff. This morning when I checked on her, she was about the same. She is not eating, walks stiff, and her stool is just water. The stool is clear water. No blood!

I am at a lose. Can you give me any suggestions to help my girl.