How to Pay the Zakah on Pigeons Kept for Trade

The questioner : A questioner says: Honorable Shaykh, I am one of those who raise pigeons, and they are for trade. I have heard that there is zakah on them, so how do I pay their zakah? Please note that some are worth fifty riyals, some are worth a thousand, and some are worth a hundred. Their value sometimes increases and sometimes decreases. I hope you will clarify how to pay their zakah, with an example if possible?

The Shaykh : Yes, when the time for zakah arrives and you have these pigeons that you are preparing for trade, appraise them, meaning determine their value. The ones worth fifty riyals, write down fifty riyals. The ones worth a thousand, write down a thousand. The ones worth four hundred, write down four hundred. The ones worth three thousand, I have been told that pigeons can reach three thousand, yes.
How? A hundred out of three thousand? Okay, these are fifty riyals, a hundred riyals, two hundred, a thousand, two thousand, three thousand, and ten thousand, a simple amount. Add them all together and see what the total is, and divide it by what?
Divide by forty, and the zakah will appear. The criterion is the value at the time zakah becomes obligatory; that is the criterion. There is no consideration for what you bought them for, nor for any increase during the lunar year that then returns and decreases. Look at their value at the time zakah becomes obligatory and pay a quarter of the highest value.