Yahya bin Muhammad bin Marwan al-Ansari (may Allah have mercy on him) said: During the expedition of Khaybar the people were struck by severe hunger, so in the presence of the Prophet (peace and blessings be upon him) they went to their donkeys, slaughtered them, and then put them in the cooking pots. While they were still boiling, their prohibition was revealed to the Prophet (peace and blessings be upon him), and the Messenger of Allah (peace and blessings be upon him) said: "The prohibition of the donkeys which you are cooking has been revealed." So the cooking pots were turned over.
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 575