What is the correct stance regarding the divergence of jurisprudential schools on the conditions of the Udhiyah (sacrificial animal), especially when the adopted Madhhab (school of thought) only permits sheep that have completed one full year and prohibits those with a cut in their ear?

The jurists have agreed that the sacrificial animal (Uḍḥiyah) is not valid if it is less than a جذع (jadha‘) of sheep. They differed on determining the age of the jadha‘: The Hanafis and Hanbalis held that it is an animal that has completed six months, while the Malikis and Shafi‘is held that it is an animal that has completed one lunar year. The jurists recommended, to avoid disagreement, slaughtering an animal that has completed one year.

As for an animal with a severed ear, they have agreed that the sacrifice is not valid with it. They differed on the extent of the damage that renders it invalid: The Hanafis said that the loss of less than one-third of the ear does not invalidate it, the Malikis said that the loss of one-third of the ear or less does not invalidate it, the Shafi‘is said that the loss of any part of the ear invalidates it absolutely, and the Hanbalis said that the loss of most of the ear invalidates it. The best is to slaughter a sound sacrificial animal to avoid disagreement.