Musannaf Ibn Abi Shayba 16:32

Abu Bakr narrated to us, he said: Ibn Ghiyath narrated to us, from Ja’far, from his father, that the Messenger of Allah (may Allah bless him and grant him peace) commanded regarding the *‘aqiqah* (sacrifice) which Fatimah performed for al-Hasan and al-Husayn, that they should send a leg of it to the midwife. He said: And no bone of it should be broken.