It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) gave orders concerning the heads of Sayyiduna al-Hasan and Sayyiduna al-Husayn, the sons of Ali bin Abi Talib (may Allah be pleased with them), on the seventh day after their birth, so they were shaved; then he gave in charity the equivalent of its weight in silver, and he did not find an animal to sacrifice (for the aqiqah).
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2562