Older girl becoming lethargic, panting at odd times, and mustard yellow diarrhea.

[spunky-chicken]

Hi, my beautiful Americana has been acting weird the last two days. She is lethargic and constantly breathing heavily. She's having mustard yellow diarrhea quite frequently and mostly just standing around. She's maybe 4-5 years old and this is a really sudden change so I don't think it has to do with age. She's our oldest chicken and our favorite so I would greatly appreciate some help.

 

[spunky-chicken]

Also if it's helpful she hasn't been laying for a few years now.

 

[spunky-chicken]

Update: the only thing that's changed in the last couple of days is a handmedown waterer. I've switched back to the old one and put some antibiotics in, hopefully we'll see some results.

 

[chrissyciaccio]

If she is older the heat can negatively impact any underlying issues- I had heavy breeds, dark Brahmas, that are prone to fatty liver disease. I learned after a necropsy that that was the case and the heat wave here was too much. They had very similar symptoms that you described- in fact I treated all three for eggbound and suspected respiratory issues, neither were found.
I have been bringing in my big girls and giving them cool(not cold) baths and letting them back out to air dry to try to bring their temps down.
Good luck! I know how frustrating it is not to know what steps to take bc so many chicken things present the same!!!