Musnad Ahmad 658:75

Yahya narrated to us, from Shu'bah, Sulayman ibn Abd al-Rahman narrated to me, from Ubayd ibn Fayruz, who said: I asked al-Bara' ibn Azib, I said: Tell me what the Messenger of Allah (peace and blessings of Allah be upon him) forbade regarding sacrificial animals, or what he disliked. He said: The Messenger of Allah (peace and blessings of Allah be upon him) stood among us—and my hand is shorter than his hand—and said: "Four are not sufficient: the one-eyed animal whose blindness is obvious, the sick animal whose sickness is obvious, the lame animal whose limping is obvious, and the broken-limbed animal that has no marrow." I said: I dislike that there be a deficiency in the tooth, a deficiency in the ear, or a deficiency in the horn. He said: "What you dislike, leave it, but do not forbid it to anyone."