Yes they definitely could use more space, as well as socialization with the rest of the flock. Older chickens are a great thing to have around for chicks, to teach them how to be chickens, but the downside is they can be aggressive to chicks so ample room overall and safe spaces (such as the panic door set up, and general clutter) are key to keeping them safe.
Do you have time to do some supervised co-mingling? Still need to provide safe spaces but it'll at least let the little ones have some time out of their brooder, while minimizing risk of injury.
