Don't know what's wrong with my chicken..?

[Flying Chickens]

She has recently started sneezing and they're pretty big sneezes. Her feet can get very hot and she sometimes stands around in the water container. She's also got diarrhoea which is runny and black. I thought it might be bird flu but she doesn't seem to have most of the symptoms. I'm quite sure that there's something wrong though- I'm just not sure what.
Any help would be appreciated, thanks!

 

[TwoCrows]

How old is she? Has she ever been wormed? I would start with worming if she has never been wormed and is older than 6 months. If she continues with the sneezing and gets other respiratory issues, then I would start her on antibiotics.

How is she today?