Hen with severe diarrhea and possibly pneumonia

[dmdhart]

One of my redstars (approx) 2 years old looked a little peakid this morning. I then noticed that her breathing was very labored. When I finally caught her, I could hear her chest rattling. It sounded like I sound when I've had pneumonia. When I picked her up, she pooped and it was extremely running, the color of egg yolk. Not sure what to treat first and what this is.
Thanks for any help and advice

 

[ChickensAreSweet]

Here's a helpful website with diagnosis charts at the bottom until someone with experience responds:
http://edis.ifas.ufl.edu/ps044

Oh, and I'd isolate her pronto! Give her scrambled egg and/or plain yogurt. Keep her warm.