krcote is right!!! I have a RIR that has gone broody twice in the past 6 months. The 1st time I gave her 10 eggs & only 4 hatched. I let her brood them for about 6 weeks in a seperate coop but then 2 months later she went broody on me again. I gave her 4 eggs this time & 2 hatched. They are now 2 weeks old & I am making her do everything as natural as I possibly can. All my chickens are free range during the day so a few days ago I opened her cage & her & her chicks are free ranging all day. So she is responsible for their protection, food, & taking them to the water bowls. She can get back in her cage anytime but so for they are loving it & she is actually doing a good job protecting them.
I hope all this work she is doing will settle her broodiness for a while.
You could try & get 2 chicks that are only a few days old & sneek them in the nest box with her at night!!!!!!!