The blood must be covered with a material halakhically classified as earth – either a substance commonly called earth or one in which seeds can be planted and grow. This includes soil, sand, manure, pulverized earthenware, ashes from burned materials, flax tow, and sawdust produced while wood is being sawed. Wet sand, which clumps rather than crumbles into fine particles, is not considered earth and may not be used. Sulfur and salt may not be used either, as they are not classified as earth (SA YD 28:23–24; Simla Ḥadasha 27–29).
The blood must be covered with earth both underneath and on top. Therefore, before slaughtering a wild animal or bird, the shoḥet should make sure that the blood will fall onto loose earth. If loose earth is already present, he should verbally designate it for the mitzva before beginning the sheḥita. After the blood has fallen onto the prepared earth, he recites the berakha and covers it with earth from above (SA YD 28:5; Shakh 12). If he mistakenly slaughtered over stones, he should move the blood onto loose earth, so that there is earth beneath it, and then cover it from above. If the blood cannot be moved, he covers it where it is; although the mitzva has not been performed in the proper manner, he still recites the berakha (SA YD 28:7; Simla Ḥadasha 8). The covering should be done respectfully, with one’s hand or with a utensil, not with the foot, lest mitzvot become degraded in his eyes (SA YD 28:6).
It is not necessary to cover every drop of blood. It is enough to cover some of the dam ha-nefesh, the vital blood that streams from the neck immediately after sheḥita. When possible, however, it is proper to cover all the blood.[2]
In poultry slaughterhouses, the blood is collected in a large vessel prepared in advance with earth or sawdust, so that the blood falls onto a substance fit for covering. At the end of each slaughtering shift, the shoḥetim cover all the blood collected there.
If the blood is absorbed into the ground after sheḥita, then as long as a visible trace of the blood remains, that trace should be covered (SA YD 28:10). If the blood was properly covered and was later uncovered by the wind, it need not be covered again, since the mitzva had already been fulfilled. If, however, the wind covered the blood with earth before the shoḥet had a chance to do so, he is exempt as long as the blood remains covered; if it is later uncovered, he must cover it himself (Mishna, Ḥullin 87b; SA YD 28:11). According to many Aḥaronim, when he covers it in this last case, he does so without a berakha (Darkhei Teshuva 81).
[2]. According to most authorities, the dam ha-nefesh that must be covered is the blood that streams from the neck immediately after sheḥita. Rema (28:15), however, writes that one should take into account the view that the dam ha-nefesh refers to the drops that emerge after the main flow has stopped, several minutes after sheḥita. In practice, this is not done in industrial slaughter, because shortly after sheḥita the animals are already moved on for skinning and cleaning, and it is difficult to wait for those later drops to emerge.
Authorities also disagree about how much of the flowing blood must be covered. According to most authorities, it is enough to cover some of it (SA YD 28:15). Some maintain that all the blood that flowed from the wound must be covered (Razah; Pitḥei Teshuva 6). In practice, the halakha follows the majority view; when it can be done without significant difficulty, one should enhance the mitzva by satisfying all opinions.
