I think with observation they should be ok as long as the older chicks aren't harassing and running over the younger ones to death and everyone is getting access to enough food and water. The age gap isn't as big in my chicks (Monday's hatch vs Thursday that same week), but my younger chicks definitely follow the lead and watch the big guys do everything first.
My only concerns would be temperature, as the day olds may need to be warmer than the more feathered out birds, and maybe any behavioral issues that might come up if they are separated later as the 2-week olds move out of the brooder and the day olds stay behind when the time comes. They may have to be reintroduced to each other but that's not the end of the world.