If you are wanting her to hatch out new eggs - then keep the chicks away from her. She will either take care of the chicks or the eggs. And she will abandon the one for the other - usually the eggs are abandoned for the chicks -but it could go the other way around. She's not going to do both the chicks and the eggs. If the eggs were about to hatch you could put the eggs and new chicks under her. But not if they have 21 days to incubate. She won't sit on the nest that long with chicks to raise.
Hope this makes sense.
That's what I had feared but I can keep her away. I plan to have the chics in one side and Broody Buff on the other. Looking forward to it all.