It is narrated from Hazrat Hujayyah bin Adi that a person asked Sayyiduna Ali (may Allah be pleased with him) about the sacrifice of a cow, so he replied that seven people can share in the sacrifice of a cow. He asked, "What if the horn is slightly broken?" He replied, "There is no harm in that." He then asked, "What is the ruling regarding lameness?" Sayyiduna Ali (may Allah be pleased with him) replied, "If it can walk to the place of sacrifice, then there is no harm." He further said, "And the Messenger of Allah (peace and blessings be upon him) commanded us to carefully examine the animal's eyes and ears (to ensure there is no defect in them)."