It has a pea comb, so is likely to be an olive egger. Its comb is small at this point, but it is early days, so that could change.
The darker barred one is a pullet, and so is the white one, which looks to be a light Sussex.
The buff Cochin is the only one I see that has a more developed comb, but it is too early to say for sure on that one, too.
If it is not clear in a couple of weeks, repost new pictures.
Best of luck.