Musannaf Ibn Abi Shayba 17:1100

Al-Fadl ibn Dukayn narrated to us, from Sulayman ibn al-Qasim, from his mother, who said: I asked Umm Sa’id, the concubine of Ali, "Did al-Hasan and al-Husayn practice augury (tataiyur)?" She said, "They would feel [the omen] but proceed anyway."