Hen & chickens ferns get their common name from their production of bulbils, or vegetative outgrowths, on the upperside of their fronds. These bulbils are the 'chickens' and the fronds are the mother 'hen'. The bulbils can grow into new individuals, as a clone of their parent.
Two hen & chickens ferns are native to New Zealand: Asplenium bulbiferum and A. gracillimum.
Most hen & chickens ferns in cultivation are actually Asplenium ×lucrosum, the false hen & chickens fern.