Rashi on Deuteronomy 14:12/רש"י על דברים י״ד:י״ב

1וזה אשר לא תאכלו מהם BUT THESE ARE THEY WHICH YOU MAY NOT EAT — This again is intended to forbid as food the bird that is slaughtered in the case of a leper (Sifrei Devarim 103:1-2; Kiddushin 57a).