Chicken suddenly lethargic, not eating, mouth open, yellow water-poop, Please Help!

[VlasicStudio]

I would ‘t do anything, but just watch for any more of them. I have had several hens develop swollen bellies thought to be reproductive disorder or water belly. They lived for a couple of years, living normally, but I would notice the yellow urates sometimes getting caught below their vents.

Thank you. I have been checking the other girls' poop and they are all fine. I'll keep Donna Summer inside at least for the rest of the day and either return her tonight or in the morning as long as she continues to do well). Her comb is now pretty much back to normal as well