Is Zakat obligatory on 64 head of sheep that a person bought from his mother, knowing that only one month remained for their original Hawl (Zakat year) with the mother, and only a few days have passed since he bought them?

Zakat is obligatory on sheep upon reaching the nisab (forty sheep) and the passing of a full year (hawl), based on the Prophet's (peace be upon him) saying: "No zakat is due on wealth until a full year has passed over it." If ownership of the wealth ceases before the completion of the year, then no zakat is due on it. Therefore, no zakat is due on your mother because her ownership of the sheep ceased before the hawl, and no zakat is due on you for them until a full year has passed from the time you acquired ownership.