deciduous hoof capsule deciduous hoof capsule in hoofed animals, the deciduous hoof capsule (capsula ungulae decidua) is the eponychium in fetuses and newborn foals. it is a deciduous structure, which disappears as the animal grows. in equines, they are shed soon after a foal begins to stand. the shedding process can vary from dropping-off whole to the gradual wearing down of the capsule. common names used in lay literature include "golden slippers", "fairy fingers", and "horse feathers".