[May a Man Spend from His Zakat on a Foundling in His Care?]

Answer—and Allah is the Granter of success: There is no impediment to that, for he is poor or needy. And if he has property—however unlikely—that is akin to the case of the stranded wayfarer cut off from his homeland and his wealth; indeed, the effective cause (ʿillah) with respect to the foundling is even more complete and clearer than for the wayfarer.
Source : Min Thimār al-ʿIlm wa al-Ḥikmah vol.1