Should I keep them together?

[Armstrong5]

I just dont really know what to do like I said I havent ever bought chicks from the feed store but the chicks just came in today so they r probably a week behind my chicks so if they r that young I will give them a week or least a couple days to get settled in but if they are about the same age I guess I will go ahead and put them together. Do you think at about two weeks on the older ones and a week on the younger ones is to old to put them together because I would feel better about waiting to see if any of the chicks from the feed store are sick or something.