Yes dividing it in half would be good
We have a little area underneath the poop board in our coop - it's wired off with a door, so we can put a broody hen down there or a bunch of chicks we want to introduce to the flock. When they see and hear each other through the wire, they start to accept each other. Then we let them free range together and soon the little chicks are part of the big happy family. There of course is going to be a literal pecking order - as long as the chicks are big enough to run out the way, they should be fine. If you notice you have an especially evil hen, you may separate her for a bit, let the chicks get into the rest of the flock, then reintroduce her.
