I'm guessing about 6 weeks? I had gotten a really mixed lot of them ranging from 1 week up. There are a few that are starting to look like this. This is one of the older ones, though. I thought so, but I'm new at this, and don't trust my judgment yet lol
Except in the last picture, with the chick in the middle, that one looks somewhat like a pullet. Do you have more pictures of him/her? Your third picture is a nice shot! All of your chicks are handsome!