Hubayrah and Umarah bin Abd narrate: We heard Sayyiduna Ali (may Allah be pleased with him) say: Sacrifice a two-toothed animal or older, and a fat one; if you eat, it will be good to eat, and if you feed others, it will be excellent food to give.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19091