"On the Day of Khaibar we ate the flesh of horses, and onagers, but the Prophet forbade us (from eating) donkeys."(sahih) (Using translation from Nasāʾī 4343)
أَكَلْنَا يَوْمَ خَيْبَرَ لُحُومَ الْخَيْلِ وَالْوَحْشِ «وَنَهَانَا النَّبِيُّ ﷺ عَنِ الْحِمَارِ»