What is the ruling on selling poultry feed if the price is determined based on the stock exchange price in a future month chosen by the client, with an upfront payment and receipt of the goods in that month? And does the ruling differ if the price is determined in advance and paid in full upfront?

The first scenario, selling the commodity at the stock market price or any other price at the time of delivery, is not permissible due to the uncertainty of the price. It is a condition that the price must be known and specified at the time of the contract. This sale constitutes gharar (excessive uncertainty) and amounts to consuming wealth unlawfully. Furthermore, it is a salaf (forward) sale, which requires the full price to be handed over at the contract session. As for the second scenario, which involves selling at a specific price determined at the time of the contract with the full price being paid at the contract session, it is permissible.