Her broodiness is more likely coincidental to the pullets arrival.
To break her broodiness you need to confine her to a small wire dog crate with no bedding in it. Elevate the crate up on 4x4s or blocks so that air can get to her belly. Keep food and water in the crate. Leave her in there all day. Let her out about an hour before roost time and watch her. If she goes back in the nest, remove her immediately and put her back in the crate for the night. Keep her in it again the next day and let her out an hour before roost again. Keep doing this until she stays off the nest and acts normal again.
If she is a game hen, the wire thing won't work. You can do it, but she will go broody again within a week of release. Only way to break the cycle is put eggs under her and let her hatch. Wire cage thing only works on breeds that don't really have that strong of a brooding instinct.