Shaybani reported,

I asked Abdullah bin Abu Awfa about the meat of domestic donkeys.He said, "Famine struck us on the day of Khaybar while we were with the Messenger of Allah ﷺ. We had captured some donkeys belonging to the people that had wandered out of the town, so we slaughtered them. Our pots were boiling when the Messenger of Allah's announcer called out, 'Overturn the pots, and do not eat any of the donkey meat.'"I asked, "On what grounds did he forbid them?"He said, "We discussed it among ourselves and concluded that he had forbidden them outright, and that he forbade them because they had not been properly drained of blood."In another narration, some of them said, "He forbade them outright because they used to eat filth."

عن الشيباني قال

سألت عبد الله بن أبي أوفى عن لحوم الحمر الأهلية؟ فقال: أصابتنا مجاعة يوم خيبر، ونحن مع رسول الله ﷺ وقد أصبنا للقوم حمرا خارجة من المدينة، فنحرناها، فإن قدورنا لتغلي إذ نادى منادي رسول الله: أن اكفؤا القدور، ولا تطعموا من لحوم الحمر شيئا، فقلت: حرمها تحريم ماذا قال تحدثنا بيننا فقلنا: حرمها ألبتة، وحرمها من أجل أنها لم تحمس. وفي رواية: وقال بعضهم: نهى عنها البتة؛ لأنها كانت تأكل العذرة.