Mahmud bin Ghaylan محمود بن غيلان العدوي مولاهم أبو أحمد · The Book on Sacrifices

That the Messenger of Allah (ﷺ) gave him sheep to distribute among his Companions as a sacrifice. "There remained a young male kid or a young billy goat, so I mentioned that to the Messenger of Allah (ﷺ) and he said: 'Sacrifice it for yourself.'" Waki' said: "The Jadha' among sheep is seven or six months."

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.