A good start.So my four 8 week old chicks have been separated in the run all week with thier own makeshift coop. A fence separates them.
It is pretty common with mine that the younger avoid the older. If they invade the personal space of the older they are likely to get pecked. It usually doesn't take them long to learn to run away and stay away. Mine usually stay in two separate sub-flocks until they are mature enough to join the pecking order. What you describe is what I'd expect to happen.I let them mingle with my 5 full grown girls and there was a lot of chasing and pecking. My little ones just hid in corner and ran away. I tried it for half hour then worried they would get too stressed. Should i wait or keep trying?
How big are your facilities? Your coop and your run? If the chicks can get away and stay away it's going pretty well. If room is too tight then you might have problems. If your run is big enough they may all be able to stay outside together. The chicks may stay in the coop when the adults are outside. Your facilities have a big effect on how this plays out. Mine do not sleep on the main roosts with the adults but find somewhere else to sleep. Hopefully your coop is big enough and set up in a way that they can avoid the adults.
I can't tell you what to do. As long as no one is getting hurt life is good. If someone is getting hurt or you are seeing something that causes you to worry, be more careful. Go slower.