The Messenger of Allah ﷺ prohibited to ride a camel which eats dung.  

نَهَى رَسُولُ اللَّهِ ﷺ عَنِ الْجَلاَّلَةِ فِي الإِبِلِ أَنْ يُرْكَبَ عَلَيْهَا  

The Messenger of Allah ﷺ forbade riding the camel which feeds on filth and drinking its milk.  

نَهَى رَسُولُ اللَّهِ ﷺ عَنِ الْجَلاَّلَةِ فِي الإِبِلِ أَنْ يُرْكَبَ عَلَيْهَا أَوْ يُشْرَبَ مِنْ أَلْبَانِهَا