One who slaughters a wild animal or a bird must cover its blood, as it is stated: “Any person from the Children of Israel or from the stranger who resides among them who hunts game, a wild animal or bird that may be eaten, shall pour out its blood and cover it with earth” (Vayikra 17:13). By contrast, the blood of a domesticated animal does not require covering, as it is stated: “You shall pour it upon the earth like water” (Devarim 12:24). Wild animals and birds share a common feature: they ordinarily live freely and must be hunted. Domesticated animals, by contrast, generally live under human care and are fed by people. True, chickens are birds that commonly live among people, but the Torah did not divide the bird category by species. Since most birds live freely, the few domesticated species are included as well (SA YD 28:1; Shakh 1).
The status of the wild ox is disputed. According to the Sages, it is a domesticated species that fled to the wilderness and became wild; according to R. Yosei, it is classified as a wild animal because it matures in the wild (Mishna, Kilayim 8:6). Most authorities rule in accordance with the Sages, so its blood need not be covered (Tur and SA YD 28:4). Some, however, are stringent and account for the view that it is a wild animal; they therefore cover its blood without a berakha (Rema YD 28:4; Kaf Ha-ḥayim 24).
Before covering the blood, one recites: Barukh ata Adonai Eloheinu melekh ha-olam, asher kideshanu be-mitzvotav ve-tzivanu al kisui ha-dam be-afar (“Blessed are You, Lord our God, King of the universe, Who has sanctified us with His commandments and commanded us concerning covering the blood with earth”). If one slaughters many wild animals or birds, he need not cover each animal’s blood separately. When he finishes slaughtering them all, he recites the berakha over covering the blood with earth and covers all the blood together (SA YD 28:9; 19:5).
The responsibility to cover the blood rests first on the shoḥet. If he fails to do so and another Jew sees the blood uncovered, that Jew must cover it, since all Israel are obligated in this mitzva (SA YD 28:8). Even if the mitzva was neglected and the blood was not covered, the meat remains kosher (Rema YD 28:1).
The obligation to cover the blood exists only when the sheḥita has rendered the meat kosher. If the sheḥita was invalid, making the animal a neveila, or if a defect was found that rendered it a tereifa, its blood need not be covered. Therefore, before the blood is covered, the knife and the cut simanim are examined, along with the standard checks for possible tereifot. If everything is found to be kosher, the berakha is recited and the blood is covered (SA YD 28:17–20).
Many explain that this mitzva reflects a moral discomfort: humanity has not yet reached the level at which eating animals would no longer be fitting, and therefore we cover the blood (Sefer ha-Ḥinukh §187). In contrast, we were not commanded to cover the blood of domesticated animals, which depend on human beings for their sustenance. Had the Torah required an act of apology even for slaughtering them, the proper moral balance would have been upset (Rav Kook, Ḥazon Ha-tzimḥonut Ve-ha-shalom 14).
