We bought a few chicks from some guy a few days ago. They were in rough shape, in a box in the heat with no food or water and seemed weak. We took them home and all of them perked up except for one. The one eats and drinks, but less than the rest, and is not as active, usually sleeps most of the day and just stands there, separate from the rest. When we pick him up, he doesn't struggle or move away from our hand like the rest do. I am not sure how old they are, but they aren't terribly young, they have feathers on their wings. Is there anything I can do?