We asked Fadalah b. 'Ubaid about the hanging the (amputated) hand on the neck of a thief whether it was a sunnan. He said: A thief was brought to the Messenger of Allah ﷺ and his hand was cut off. Thereafter he commanded for it, and it was hung on his neck.  

عَنْ تَعْلِيقِ الْيَدِ فِي الْعُنُقِ لِلسَّارِقِ أَمِنَ السُّنَّةِ هُوَ قَالَ أُتِيَ رَسُولُ اللَّهِ ﷺ بِسَارِقٍ فَقُطِعَتْ يَدُهُ ثُمَّ أُمِرَ بِهَا فَعُلِّقَتْ فِي عُنُقِهِ