We got them as chicks and now they are laying so their not really new. I can't lock them in because all the other chickens need to go in the coop to lay eggs, rost and eat food.
Are they properly integrated with the other birds (do they get along out in the run, any competition for food or other resources, any bullying)? I would think they would've just followed the older birds as they grew up.
Is there anyone you know who is comfortable enough around chickens to put them in the coop at night for you while you're gone? Don't know how soon your trip is but that's the "easiest" solution for now, as it doesn't rely on training the birds...