While everyone on this thread is more experienced than I am, and usually know a lot more than I do, one of the two most common problems with chicks involves the need for extra vitamins (wry neck, weakness, etc.), and the second is the need for Corid (coccidiosis) at times. When I hatch, I automatically add a little Rooster Booster to the waterer. This compensates, and gives a little extra oomph in case the feed is not quite as fresh from the feed store, lacking full potency. Another thing, even if they don't eat much for whatever reason, they still require the nutrition, so I ensure they are getting some through their water. I do this for about 3 weeks, then go to plain water. I've never had to treat with Corid, but I've got it on hand just in case.