"Not every hen is willing to be broody and hatch eggs. Broodiness means your hen wants to set on eggs for the next twenty-one days, until they hatch. Because hens stop laying eggs when they are brooding, breeders have selected hens that don't get broody. Broodiness is a behavioral trait that doesn't appear in the show ring, so unless breeders want it, they may select against it. It's a traditional trait that allows flocks to replenish themselves, so heritage breeds should be good broody hens."