The Shaykh (Al-Mufid), may Allah سبحانه وتعالى support him, narrated to me from Abu al-Qasim Ja'far ibn Muhammad, from his father, from Sa'd ibn Abdullah, from Ahmad ibn al-Hasan ibn Ali ibn Faddal, and Amr ibn Uthman, from Amr ibn Sa'id al-Mada'ini, from Musaddiq ibn Sadaqah, from Ammar al-Sabati, who said: Abu Abdullah عليه السلام was asked about a man who slaughtered a bird, and its blood fell into a well. Imam عليه السلام said: "Draw some buckets from it. If the bird was properly slaughtered (i.e., zaki), then this is sufficient. As for other things that fall into a well and die in it, the most severe is a human, for which seventy buckets must be drawn. The least severe is a sparrow, for which one bucket is sufficient. Anything else falls between these two."