Musannaf Ibn Abi Shayba 36:357

Abdullah ibn Numayr narrated to us, he said: Muhammad ibn Ishaq narrated to us, from Abdullah ibn Damra al-Fazari, from Abdullah ibn Abi Sulayt, from his father, Abi Sulayt—and he was a Badrī (a participant in the Battle of Badr)—who said: The prohibition of the Messenger of Allah, peace and blessings of Allah be upon him, reached us regarding the eating of donkeys, while the cooking pots were boiling with them. He said: So we overturned them upon their faces.