We have been having unseasonably hot (for us -- we are in coastal San Diego) weather here and our chicks are in our bathtub where there isn't much breeze. I thought they were hot so we put a small fan pointing down into one end of the tub and gave them ice and watermelon. However, I checked them this morning when it was cooler and the biggest one is definitely panting and shaking her head. They have been outside and have had bugs and worms and been in the dirt. My husband checked her throat while I held her wrapped in a towel (is there an easier way to get in a chcken's mouth because she was not having it and it took a long time) and couldn't see anything. They have had acidulated water since we got them at a couple of weeks old. I have a video if that helps... could it be the heat? help? Before this I helped look after chickens for 6 months when I was a teen (in a hotter place than this) and the "only" problems we had were predators, we never had any sickness and the birds dealt fine with the heat.