What is the detailed ruling on trading in the sale of pigeon eggs?

For pigeon eggs to be sold, they must be present, have value, be pure, and be possible to benefit from and deliver. Therefore, it is not permissible to sell rotten eggs or eggs that have not yet hatched.

Scholars have differed on whether eggs are considered ribawi (subject to usury laws) or not, with two opinions: - The Hanafis, Hanbalis, Ibn Sha'ban from the Malikis, and the old opinion among the Shafi'is do not consider them ribawi, and they permit selling one egg for two eggs. - Whereas the Malikis (other than Ibn Sha'ban) and the new opinion among the Shafi'is consider them ribawi, thus not permitting differentiation (tafadul) or delay (nasa') in their sale.

They also differed on salam (selling eggs for eggs with delayed delivery). The majority do not permit it, while the Hanbalis permit it.

The majority agreed on the permissibility of salam in eggs if their type and description are known, and their quantity and description can be precisely determined.