Sahih Muslim Book 18, Hadith Number 4278.
Chapter : Stray thing found by anyone.
Zaid b. Khalid al-Juhani reported that Allah’s Messenger (may peace be upon him) was asked about picking up of stray things, whereupon he said: Make announcement of that for one year, but if it is not recognised (by the owner), then recognise its big and strap, then eat it; and if its owner comes, then give that to him. This hadith has been narrated on the authority of Al-Dahhak b. Uthman with the same chain of transmitters but with a slight variation of words.