I have 10 baby Austrolorps all about 5 days old. They have all been pretty active up until tonight. There is one that is a little smaller than the rest and she is just laying there with her head down. We put a cricket in the brooder tonight and the rest of the chicks went crazy running around but she didn't even look up. When I hold her in my hands, she doesn't squirm or try to escape like the others do and she won't eat. Any suggestions? Should I seperate her from the rest to avoid a sickness among the whole group?