Sahih Bukhari Volume 007, Book 067, Hadith Number 409.
Narrated By Ka'b : That a slave girl of theirs used to shepherd some sheep at Si'a (a mountain near Medina). On seeing one of her sheep dying, she broke a stone and slaughtered it. Ka'b said to his family, "Do not eat (of it) till I go to the Prophet and ask him, or, till I send someone to ask him." So he went to the Prophet or sent someone to him The Prophet permitted (them) to eat it.