An ancient custom from the days of the Geonim, is to do a sort of “sacrifice” with a chicken before Yom Kippur—“a soul in place of a soul”—to awaken us to repent with all our heart and soul. In order that it should not appear as offering sacrifices outside the Temple, this species was chosen, which is never brought upon the altar. A rooster is taken for a man and a hen for a woman (if possible, one for each individual). It is preferable they be white, as it is said (Isaiah 1:18): “If your sins prove to be like crimson, they shall become white as snow.” Verses are recited, and it is swung around the head.
Above all, it is important that the slaughter and inspections be carried out in accordance with halacha. According to the AriZal , the kapparah is similar to the scapegoat (se’ir hamishtale’ach), which atones for all the sins of Israel, and its primary function is in the act of slaughter. Thus, if there was a flaw in the slaughter, another kapparah is required; but if the slaughter was valid, even if it was later found the bird was trefah, the kapparah has been fulfilled.
It is customary to give the chicken to the poor. Care must be taken that the chicken is first kashered properly, or at least ensure that the recipient will prepare it in accordance with halacha. Some redeem the kapparot and give their value to the poor, so that they will not be embarrassed by receiving our sins. The internal organs are customarily thrown to feed animals, as it is proper to have compassion on G-d’s creatures so that Heaven will have compassion on us. One who is unable to perform kapparot with a chicken should do so with a fish, and if that is also not possible—then with money, which should be given to charity.
translated from Sichat HaShevua
