Rabbits are common wild animals in the Stronghold Series games.
They are very fast pests, eating up any plants they can find. They like farmlands and they are also harmful, as they eat not only grass, but crops, including wheat and hops. Farmers will constantly try to make their lands fertile, but rabbits will stay and kill anything that has grown so far. Not to mention, rabbits breed very-very fast and they can quickly overwhelm the map.
Fortunately, any unit that meets them will attack them (missile units after instruction). Rabbits are so fragile that they will die from a weapon swing or shot. Lions will also go after rabbits.
Rabbits may spawn from an event available in the Castle Builder or predefined in custom missions.