The Custom of Kapparos
Some have the custom of performing the rite of Kapparos [symbolic atonement] on the day preceding Yom Kippur; if it is not possible to do so then, the rite may be performed earlier.
The rite consists of gently taking a chicken in one's hand and reciting a prayer. A man takes a rooster; a woman takes a hen; a pregnant woman takes two fowls - a hen and a rooster. Optimally, the fowl should be white to symbolize purification from sin, as the verse (Isaiah 1:8) states: And if your sins be like scarlet, they shall become as white as snow. One need not, however, make an excessive effort to find a white fowl.
If a rooster or a hen is unavailable, one may substitute other fowl or animals; even a fish may be used for the rite. However, one should not use doves, since doves were brought as sacrificial offerings in the Temple, and this may give rise to the mistaken impression that the Kapparos are a form of sacrifice.
The fowl [or other animal] used for Kapparos is taken in the right hand and the appropriate text from the prayer book is recited. The bird is then gently waved over one's head three times and the appropriate text is recited.
The word Kapparos [like kippur] means "atonement," and is used to refer to the chickens themselves, but one should not think that Kapparos themselves serve as a source of atonement. Rather, they serve as a means to bring a person to the awareness that he might very well be deserving of death because of his sins and he will thereby be motivated to repent and ask G-d for mercy.
The fowl is then slaughtered by an expert butcher in accordance with halachic procedure.
At Anshei Lubavitch we use only free range chickens from a local farm, which are then distributed to the needy.