It sounds so simple -- just get a hen prone to broodiness. Except hatcheries don't select to preserve that trait and a great many hatchery Silkies disappoint their owners who wanted a broody by being either disinterested or male.
I have a Marans hen from a breeder that I thought for certain would go broody. As soon as it starts getting cold out, she will sit on any egg left in the nest at dusk. All night if I don't show up to collect. Weirdest thing I've seen. But, as soon as the sun is out, she's done until the next evening. I tried enticing her by leaving a clutch of fakes in place, she didn't bite.