The Prophet (SWAS) and his companions used to sacrifice the camel with its left leg tied and it remained standing on the rest of his legs.
Sunan Abi Dawud Book 11, Hadith 47
← Previous Hadith I was present with the Messenger of Allah (ﷺ) at the Farewell Pilgrimage. When the sacrificial camels were brought to him, he said: Call AbulHasan (Ali) to me. Ali was then called for and he (the Prophet) said to him: Catch hold of the lower end of the lance, and the Messenger of Allah (ﷺ) himself caught hold of the upper end. He then pierced the camels with it. When he finished slaughtering, he rode on his mule and mounted Ali behind him.

Sunan Abi Dawud Book 11, Hadith 46 Next Hadith → I was present with Ibn `Umar at Minah. He passed a man who was sacrificing his camel while it was sitting. He said make it stand and tie its leg ; thus follow the practice (sunnah) of Muhammad (SWAS).

Sunan Abi Dawud Book 11, Hadith 48