Hens and chickens forms a tight rosette "hen" that steadily produces tiny offset "chicks" around its base, spreading into a charming, low mat that thrives with almost total neglect.
Unlike most succulents, Sempervivum tolerates real winter cold, making it one of the few true succulents that can be grown outdoors year-round in temperate climates, right in a rock garden or stone wall crevice.
Hens and chickens want full sun and sharply draining soil or gritty rock garden mix, and they're remarkably drought and cold tolerant once established. The individual rosette ("hen") dies after flowering, but its many offset "chicks" quickly fill in the gap.
Excess water, not cold, is what most often kills hens and chickens — good drainage matters more than winter protection in most climates.