Baffled.....

One of my rhode island red hens is sick. I'm baffled by what it could be though. I noticed a few days ago that she seemed off but wasn't worried because she was eating and drinking. Today I noticed her comb was flopped over,almost colorless and she was almost lethargic. I put her in the dog crate we use for quarantine in my bathroom and gave her some electrolytes to begin with. I started researching what it could be and have just about been able to eliminate everything. I did find some identify the problem by the color of their poop pictures and the only one that looked like her poop was the cancer one. She has a weird metallic scent coming off her and I was able to rule out any wounds. Also I did catch my huge male goose trying to mate with a different chicken a few days back. She is getting fluid but hardly defecating and when she does its tiny little bits of green chunks in white liquid with some yellow. Any ideas?