If I buy 30 sheep, then they reproduce

Q 3: A man who owns some camels sells one of them in return for 40 sheep. When the sheep are delivered, the Zakah (obligatory charity) collector asked him to pay Zakah for these sheep even though a year had not passed since he took possession of them. Is Zakah payable where there are forty sheep and a year has not passed since they came into a person's possessed?

A: If the man has the value of camels which reaches the Nisab (the minimum amount on which Zakah is due), which is one fifth of the price of camels, then he sells one of them in return for 40 sheep before one year passes with the camels in his control, paying Zakah depends on his intention when he did this act. If he does so to wangle his way out of paying the Zakah of the camels and to begin a new year for the sheep starting from the delivery date, he is obliged to pay the Zakah which is one sheep according to the said amount of sheep he owns as a way of Sadd-ul-Dhara'i` (blocking the means leading to sins), penalizing him for his ill intention and punishing whoever acts fraudulently in religious issues. The Prophet (peace be upon him) said: “Separated properties should not be joined nor joined properties be separated for fear of (having to pay more) Zakah.” On the other hand, if he does so intending to increase his wealth [trading], and not to escape the obligation of paying the due Zakah, there will be no Zakah on the camels due to the lack of Nisab nor on the sheep (Part No. 9; Page No. 214) because they have been in his possession for less than one year.May Allah grant us success. May peace and blessings of Allah be upon our Prophet Muhammad, his family and Companions!