That the Messenger of Allah (ﷺ) said: "There is no Fara' or 'Atirah."The Fara' is the first of the offspring that would be born to them, so they would slaughter it.The 'Atirah was an animal that they would slaughter during Rajab to honor the month of Rajab, since it was the first of the sacred months.

They entered upon Hafsah bint 'Abdur-Rahman to ask her about the 'Aqiqah. She informed them that 'Aishah had informed her, that the Messenger of Allah (ﷺ) ordered them that for a boy, two sheep were sufficient, and for a girl one sheep.

That his father said: "I saw the Messenger of Allah (ﷺ) say the Adhan in the ear of Al-Hasan bin 'Ali - when he was born to Fatimah - the Adhan of Salat."

Another chain with similar.

That she asked the Messenger of Allah (ﷺ) about the 'Aqiqah. He said: "For the boy is two sheep, and for the girl is one, it will not harm you if they (i.e. the sheep) are male or female."

That the Messenger of Allah (ﷺ) said: "The best of Udhiyah (sacrifice) is a ram, and the best (burial) shroud is the Hullah."

"We were standing with the Prophet (ﷺ) at 'Arafat when I heard him say: 'O you people! For every household each year is Udhiyah (sacrifice) and 'Atirah. Do you know what an 'Atirah is ? It is that which you call Ar-Rajabiyyah.'"

That Ali bin Abi Talib said: "The Messenger of Allah (ﷺ) had the 'Aqiqah for Al-Hasan with one sheep, and said: 'O Fatimah! Shave his head and give the weight of his hair in silver as charity.'" He said: "So I weighed it, and it was the weight of a Dirham or a bit of a Dirham."

From his father, that the Prophet (ﷺ) gave a Khutbah, then he descended and called for two rams and slaughtered them.

"I attended the Eid Al-Adha' with the Prophet (ﷺ) at the Musalla. When he finished his Khutbah, he descended from his Minbar and was given a male sheep. The Messenger of Allah (ﷺ) slaughtered it with his hand and said: 'Bismillah, Wa Allahu Akbar, this from me and whoever does not slaughter from my Ummah.'"

Another chain with similar meaning.

That the Prophet (ﷺ) said: "Whoever sees the crescent of Dhul-Hijjah, and wants to slaughter a sacrifice he should not take from his hair nor from his nails."