If you want to encourage broodiness, keep wooden eggs in the nesting boxes and remove the real ones. If they see a nice big clutch of eggs, they might get the urge. If I wanted a broody, I would choose from a broody breed, not BRs, but it can happen. I have even had a white leghorn go broody on me once.
If ya'll can't get any new chickens now, maybe you can trade one of your hens for another that is a cochin, buff orphington, silkie or araucana.
I know a lot of people are trying to hatch out chicks now, but personally, I would hold off until next spring.