Sayyiduna Ali (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) ordered him to stand over the sacrificial camels and that "their meat, hides and saddle-cloths be distributed among the poor, and that nothing of them be given to the butcher as his wages."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 10242