It wasnarrated that Nubaishah said:
"A man called the Messenger ofAllah(ﷺ) and said: 'O Messenger of Allah, we used to sacrifice the'Atirah during the Ignorance days in Rajab,; what do you command ustodo?' He said: "Sacrifice to Allah whatever month it is, dogood forthe sake of Allah and feed (the poor).' They said: 'OMessenger ofAllah, we used to sacrifice the Far'ah during theIgnorance days; whatdo you command us to do?' He said: 'Forevery Sa'imah* (flock ofgrazing animals), feed the firstborn asyou feed the rest of yourflock until it reaches an age where itcould be used to carry loads,then sacrifice it, and give its meat incharity' – I** think he said –'to the wayfarer, for that isgood.'"
English reference: Vol. 4, Book 27, Hadith 3167
Arabic reference: Book 27, Hadith 3287