Sayyiduna Jabir (may Allah be pleased with him) reports this saying of the Prophet (peace and blessings be upon him): "For the young in the womb (of an animal), the slaughter of its mother counts as its slaughter, provided it has grown hair." (Allamah al-Haythami says:) I say: Abu Dawud also recorded this narration, but he did not record the words "provided it has grown hair."
Abu Ya'la recorded it; its chain contains Hammad bin Shu'ayb, who is da'if (weak).