A Brooklyn rabbi says he was bombarded with e-mails and letters from animal-rights activists because of a ritual performed during the Jewish holidays.

Rabbi Shea Hecht says during the Jewish New Year he received more than 1,000 e-mails in an hour, some of which were threatening and anti-Semitic.

The backlash stems from a Jewish ritual known as Kaparot, in which chickens are slaughtered. The group People for the Ethical Treatment of Animals shot a video of the ritual, which they say shows people waving chickens over their heads as a way to symbolically transfer their sins to the chicken. The chicken is then slaughtered during Yom Kippur, or Day of Atonement.

Hecht says the ritual is 2,000 years old and that the chickens were handled and slaughtered in the most humane way possible.