What is the minimum age requirement for a sacrificial animal other than the penalty for hunting (Jaza' al-Sayd)?
Chapter on Ransom (Fidyah) and Penalty for Hunting
Al-Mughni
Book of Hajj
Primary text
For offerings other than the penalty for hunting, such as the sacrifice associated with Tamattu', the minimum requirement is the Jadh' (a young sheep) of the flock, which has completed six months of age. For other categories of animals, the requirement is the Thani (an animal that has completed its first year and is entering its second). Specifically, the Thani for a goat must be one year old, for cattle two years old, and for camels five years old. This ruling is supported by Malik, Al-Layth, Al-Shafi'i, Ishaq, Abu Thawr, and the Ashab al-Ra'y (Hanafi scholars). The evidence is found in the Hadith transmitted by Jabir, which states: 'Do not slaughter except a Musinnah, unless it becomes difficult for you, in which case slaughter a Jadh' of the sheep.' This narration is also found with Muslim and Abu Dawud.
Supporting text
Ibn Umar and Al-Zuhri maintain that only the Thani from every type of animal is sufficient. Al-Atta and Al-Awza'i hold that the Jadh' is sufficient for everything except goats.