Firstly: There is a difference of opinion among the schools of thought regarding this matter, and the opinions are as follows:
– It is valid to share in an udhiyah, whether in its cost or in its reward, according to the consensus of three major schools of thought: the Hanafi, Shafi’i, and Hanbali schools.
– Sharing in the cost is not valid; only sharing in the reward is valid. This is the opinion of the Maliki School.
Secondly: It is valid to share in an udhiyah, particularly when it comes to camels or cows. If seven individuals share in a cow or camel, it is valid as long as the share of each person is not less than one-seventh. If the participants are more than seven, it is not valid. However, if they are fewer, it is valid. Sacrificial animals are only valid when they come from specific livestock including camels, cows, buffaloes, and sheep. – Based on this, it is not valid in our view for one person to share in a ewe with others.
And Allah knows best.
Fatwa by Dr. Khālid Naṣr