Is the peacock kosher?
Unlike mammals, the Torah does not specify signs to differentiate between kosher and non-kosher fowl. The Torah (Devarim 14:11-21) lists twenty-four types of forbidden fowl (eg. owl). All other fowl are assumed to be kosher (eg. chicken).
However, the Mishnah mentions four signs to identify non-kosher fowl (Chullin 3:6). Since we lack the experience to apply these rules (though the peacock appears to follow them), for all intents and purposes we are permitted to eat only those birds that we have a tradition regarding their being kosher (Rema, Yoreh De’ah 82:3; see also Shulchan Aruch 82:2).
Based on these principles, the Kenesses Hagedolah (Yoreh De’ah 82:31) writes that we cannot eat the peacock, because of a lack of clear tradition. Although he mentions early sources (including Rashi) that indicate the kashrut of the bird, he adds that because we don’t have a clear tradition, we cannot rely on our assumption that our peacock is the same bird.
Some poskim write that the peacock is a kosher fowl (see Tel Talpiot 16 (5667), p. 148-49, but see p. 164; Olam Hatushia p. 66-9), but this is only in the framework of a theoretical discussion, and not a halachic permit to actually eat the bird.
It is further noteworthy that in certain places, in particularItaly, there was clearly a tradition that the peacock is kosher (Pachad Yitzchak Vol. 6, p. 68; Zivchei Cohen, Livarno 1832, no. 7).
However, this tradition has not been continued, and in our days in Israel/America, the peacock will therefore not be eaten.