My one year old Americana is acting lethargic - panting staying in run - watery clear poops n

It sounds like it's hot where you are and she's likely overheating. Make sure you give your chickens cold water and maybe give her a cold bath to cool her down. Also try giving her watermelon so she is getting some food and to make sure she's getting water so she doesn't get dehydrated. Keep a good eye on her, I'm only assuming it's from the heat maybe someone else with more experience can diagnose it... Chickens get diarrhea and pant when it's too hot, the diarrhea is from drinking more water than normal but as far as I know it's normal in hot weather.