Anas b. Malik reported: When it was the Day of Khaibar a visitor came and said: Messenger of Allah, the asses have been eaten. Then another came and said: Messenger of Allah, the asses are being destroyed. Then Allah's Messenger (ﷺ) commanded Abu Talha to make an announcement that Allah and His Messenger have prohibited you (from eating) of the flesh of (domestic) asses, for these are loathsome or impure. He (the narrator) said: The earthein pots were turned over along with what was in them.
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا مُحَمَّدُ بْنُ مِنْهَالٍ الضَّرِيرُ، حَدَّثَنَا يَزِيدُ بْنُ زُرَيْعٍ، حَدَّثَنَا هِشَامُ بْنُ حَسَّانَ، عَنْ مُحَمَّدِ بْنِ سِيرِينَ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ لَمَّا كَانَ يَوْمُ خَيْبَرَ جَاءَ جَاءٍ فَقَالَ يَا رَسُولَ اللَّهِ أُكِلَتِ الْحُمُرُ . ثُمَّ جَاءَ آخَرُ فَقَالَ يَا رَسُولَ اللَّهِ أُفْنِيَتِ الْحُمُرُ فَأَمَرَ رَسُولُ اللَّهِ صلى الله عليه وسلم أَبَا طَلْحَةَ فَنَادَى إِنَّ اللَّهَ وَرَسُولَهُ يَنْهَيَانِكُمْ عَنْ لُحُومِ الْحُمُرِ فَإِنَّهَا رِجْسٌ أَوْ نَجِسٌ . قَالَ فَأُكْفِئَتِ الْقُدُورُ بِمَا فِيهَا .
sunnah.com