One of our 3-4 week old chicks (Barred Rock) seems to be not as active as the others and has her eyes closed quite a bit. She doesn't have the same vigor her sisters do. My wife said she seems sad and we are getting a bit worried there is something wrong. We have seen her eating and drinking but when she isn't she spends most of her time under the heat pad while the other 3 spend most of their time scratching in the brooder and chasing each other. I have not seen poop to comment on that in the last 24 hrs. Below is a pic of her with her eyes closed while being held. Can someone help me know what could possibly be going on and what i could or should be doing (if anything)?