Houdans are a top-hat breed. They are black with white speckles and will lay a white egg. They will need to be kept protected from aerial predators (hawks, owls) since they have trouble seeing sometimes. Two pullets for $12 is not a bad deal for Houdans, since they are classified as a rare and unusual breed.
But in reality, they're as "rare" as any other hatchery bred breed, because chances are, they're from a hatchery.
Originally Houdans were a large, meaty, dual purpose breed with a beautiful "fancy" touch of having a mottled color and a tophat with a beard and muffs. . . But now hatcheries have ruined them, and there's hardly any good breeder stock left out there, if any at all, so they're only good as a lawn ornament and white eggs.