Abu Dawud Book 27, Hadith Number 4116.
Chapter : The view that skins of dead animals should not be made use of.
Narated By Abdullah ibn Ukaym, : Al-Hakam ibn Uyaynah said that he went along with some people to Abdullah ibn Ukaym, a man of Juhaynah. al-Hakam said: They entered and I sat at the door. Then they came out and told me that Abdullah ibn Ukaym had informed them that the Apostle of Allah (PBUH) had written to Juhaynah one month before his death: Do not make use of the skin or sinew of an animal which died a natural death.