Is it permissible to partner with siblings in purchasing a Udhiyah cow with cash, on the condition that the delivery takes place on the first day of Eid al-Adha?

The majority of scholars hold the permissibility of salam (forward contract) in animals, citing as evidence that the Prophet, peace and blessings be upon him, "borrowed a young camel from a man, then commanded that the man be repaid his camel. They said, 'We only find a quadragenerian (a camel in its fourth year).' He said, 'Give it to him, for the best among people are those who are best in repaying debts.'" This indicates that animals are among the things whose characteristics can be precisely defined.

As for the hadith (definition) prohibiting the sale of an animal for an animal on credit (deferred payment), its authenticity is disputed. Those who authenticate it interpret its meaning to apply when both animals are on credit. However, if one is present and the other deferred, there is no harm.

It is permissible for more than one person to participate in a salam contract. Their liability before the seller (muslam ilayh) is collective, and they then divide the received goods according to their agreement.