Musnad Abu Ya'la al-Mawsili 114:5

Ubayd Allah ibn Umar narrated to us, Hammad ibn Zayd narrated to us, from Hisham, from Muhammad, from Anas—and Ayyub from Muhammad, Hammad said: "I think it is from Anas"—who said: The Messenger of Allah (ﷺ) was approached on the day of Khaybar, and it was said to him: "The donkeys have been eaten." So he ordered Abu Talhah to announce: "Indeed, Allah and His Messenger forbid you from the meat of domestic donkeys, for it is a rijs (abomination/impurity)." They said: "So the cooking pots were overturned."