One of my chickens was sitting on the roost by itself. I noticed she looked a little bigger. When I got closer I couldn't believe how swollen she was. Compared to the others she was one and a half times their size. I picked her up and fluid came out of her mouth. We took a closer look at her and she was very lethargic. I had put scratch down that I make up and some corn and she didn't touch it. We applied some stroked to her chest and belly and more fluid came out and it was brown. I don't know what to do or how to help her. I don't want to lose her. Does anyone have any ideas of what this is or what I can do for her? Please.