Remove the eggs at night while she is sleeping to avoid being pecked, then remove the hen from he nest and shut her out. It will upset her but the only way to break a hens broodiness is to keep her from sitting on the eggs.
A hen goes broody when her hormones tell her it' time to become a mother, and they don' know if their eggs are fertile or not but will usually continue to sit for a long time in hope of them hatching. Usually they give up eventually , bit it just takes a lot out of them health-wise so it is not good for them to sit too long.
You should try to simply shut her out of the nest and see if this breaks her broodiNess. It may take a couple of days or evwn longer. Some hens are very stubborn and will just sit on the ground outside the nest, imagining they are still on their eggs. Keep shoving them outside with the flock and if they persist in sitting around you will have to make a 'broody breaker' which is a crate or cage of some sort with a wire mesh type bottom and which is elevated off the floor such as on a few bricks etc. This allows cool air to circulate under he hen to prevent her keeping her underside warm and causes her to give up brooding.
Or you could just give her a chick or two!
