Sometimes just taking her off the nest, giving her some treats in the run, and letting her hang for a bit is enough. If she’s really determined, you may have to shut her out of the nest, or put an ice pack under her when she sits on it. As a last resort, you can put her in an elevated cage for a...
Broodiness lasts until the hen gets bored (more often than not) or she’ll perch on the eggs for three weeks until they hatch. Occasionally a broody will just pancake herself over unfertilized eggs, wooden eggs, or even no eggs. That’s when you gotta take action.