Abu Dawud Book 28, Hadith Number 4180.

Narated By Abdullah ibn Ja’far : The Prophet (PBUH) gave the children of Ja’far three day’ time to visit them. He then came to visit them, and said: Do not weep over my brother after this day. He said: Call to me the children of my brother. We were brought to him as if we were chicken. He said: Call a barber to me. He then ordered and our heads were shaved.