The pre-Yom Kippur custom that may involve swinging a chicken or money over a person’s head is kapparot.
Kapparot is an atonement ritual practiced by some Jewish communities, especially Orthodox Jews, on the eve of Yom Kippur. The Hebrew term is related to kapparah, meaning atonement. In the chicken version, a rooster or hen is waved over the head while prayers ask that severe decrees be transferred symbolically to the bird; it is then slaughtered according to Jewish law and commonly given to charity or used as food.
Many people use money instead. A bag or sum of money is swung around the head and donated to the poor, making this version more practical and avoiding concerns about rushed or improper slaughter. Kapparot is not universally observed: rabbis including Joseph Karo opposed it, while Moses Isserles supported it. It is also distinct from tashlikh, the Rosh Hashanah custom of symbolically casting sins into water.