Musnad Ahmad 175:2

Waki’ narrated to us, from Usamah ibn Zayd, from al-Zuhri, from a son of Ka’b ibn Malik, that a slave girl of Ka’b was grazing sheep of his at Sal’. A wolf attacked one of her sheep, and the shepherdess reached it and slaughtered it with a flint stone. Ka’b ibn Malik asked the Prophet, peace and blessings of Allah be upon him, and he commanded him to eat it.