Mass. Gen. Laws ch. 94 § 139G
Nothing in sections one hundred and thirty-nine C to one hundred and thirty-nine E, inclusive, shall prohibit, abridge, or in any way hinder the religious freedom of any person or group, and, in order to protect freedom of religion, ritual slaughter and the handling or other preparation of livestock for ritual slaughter shall be exempt from the provisions of said sections. In this section the term "ritual slaughter" means slaughter in accordance with the ritual requirements of the Jewish faith or any other religious faith that prescribes a method of slaughter whereby the animal suffers loss of consciousness by anemia of the brain caused by the simultaneous and instantaneous severance of the carotid arteries with a sharp instrument.
Mass. Gen. Laws ch. 94, § 139G