Musannaf Ibn Abi Shayba 16:95

Abu Bakr narrated to us, he said: Abdullah bin Numayr narrated to us, he said: Muhammad bin Ishaq narrated to us, from Abdullah bin Amr bin Damra al-Fazari, from Abdullah bin Abi Sulayt, from his father, Abi Sulayt—and he was a Badr-veteran—who said: The prohibition of the Messenger of Allah, peace and blessings of Allah be upon him, regarding the eating of donkeys came to us while we were at Khaybar. And indeed, the cooking pots were boiling with them, so we overturned them onto their faces.