The Torah obligation of Kisui Ha’dam requires covering the blood of a bird that falls to the ground after slaughtering. Therefore, those who observe the custom of Kapparot on Ereb Yom Kippur must ensure that the blood is covered after the chicken is slaughtered.
As a Beracha may not be recited in a place with a foul odor or refuse, and Berachot are recited over the slaughtering of a chicken and the covering of the blood, one must ensure that the slaughtering is done in a clean area. Often, the slaughtering site is a place with filth and a stench; care must be taken to ensure the cleanliness of the area so the Berachot may be recited.
The obligation to cover the blood requires placing two layers of earth – one directly on the ground beneath the blood, and another over the blood after the slaughtering. Therefore, one must ensure that there is earth on the ground before the animal is slaughtered. The Shulhan Aruch writes that one must verbally designate the earth on the ground as earth for fulfilling the Misva, and he then cites a different opinion ("Yesh Omerim") that a verbal designation is not necessary. In light of the rule of "Stam Va’yesh Halacha Ki’stam," Hacham Bension Abba Shaul (Israel, 1923-1998) writes that the Shulhan Aruch accepted the first opinion, and thus one should verbally designate the earth on the ground. The earth which one places over the blood does not require verbal designation, and one picks it up with his hands, which suffices as a formal designation.
The earth used for Kisui Ha’dam must be "Afar Tiho’ah" – dry earth that can be crumbled into granules, as opposed to a lump of moist earth.
If, after slaughtering, the blood is immediately absorbed into the ground, one must nevertheless cover it if there is a visible trace of the blood. This is the ruling of the Shulhan Aruch. If the earth placed over the blood absorbs all the blood and its trace can be seen in the earth, it should be covered again, though without a Beracha. If the wind covers the blood with earth, and there is no visible trace of the blood, then one is exempt from the Kisui Ha’dam obligation and does not have to cover the area. If the blood was exposed after it had been covered, one is not required to cover it a second time.
Before covering the blood, one should take the dirt in his hand, have in mind to fulfill the Torah command of Kisui Ha’dam, and then recite the Beracha, "Baruch…Asher Kideshenu…Ve’sivanu Al Kisui Ha’dam Be’afar." One does not recite "She’he’hiyanu" over the Misva of Kisui Ha’dam, as the Misva is not bound to any particular time period.
According to the Shulhan Aruch, one does not have to cover all the blood that falls from the neck after slaughtering. Rather, one must cover only the first few drops that fall ("Dam Ha’nefesh"). Others maintain that the first stream of blood that falls after the initial few drops is also included in the obligation. There is also an opinion which requires covering all the blood. Hacham Ovadia Yosef rules that as we deal here with a Biblical obligation, it is proper to satisfy all opinions and ensure to cover all the blood that falls to the ground after slaughtering.
One must cover the blood with either one’s hand, or some instrument or other object held in his hand. One should not kick the dirt over the blood, as this would be disrespectful to the Misva.
Strictly speaking, the Shohet (person who slaughtered the chicken) is given the privilege of performing this Misva of Kisui Ha’dam, as the Torah indicates in formulating this obligation ("Ve’shahat Et Damo Ve’chisahu Be’afar" – Vayikra 17:13). However, the Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909) writes that if the Shohet is slaughtering a large number of chickens (as is usually the case on Ereb Yom Kippur), then the owner of the chicken should be given the privilege of performing this Misva. If he is having several chickens slaughtered, then he may invite his family members to perform the Misva, as well. However, Kisui Ha’dam must be performed only by adults who have certainly reached physical maturity (to the exclusion of minors), and only one Beracha is recited per chicken.
According to some authorities, once some of the blood is covered, one can no longer recite a Beracha before covering the rest of the blood, since, as we have seen, the Shulhan Aruch rules that the Misva is fulfilled if even some of the blood is covered. However, this applies only if a person covered some of the blood. If the wind blew earth over some of the blood, one recites a Beracha before covering the rest.