I received 9 chicks in the mail today. It looks like they range from a few days old to a couple of weeks. One was DOA. The rest all drank water with sugar and chick saver in it as soon as I put them in the brooder. The four oldest are doing fine. Of the four youngest, two are eating and drinking but two are just huddled under the lamp with eyes shut and crops empty. These are the first chicks I have ever received. What should I do for the two littlest guys?