Mass. Gen. Laws ch. 94 § 139C
As used in this section and sections one hundred and thirty-nine D to one hundred and thirty-nine G, inclusive, the following words shall have the following meanings:
"Commissioner", the commissioner of public health.
"Slaughterer", any person regularly engaged in the business of (1) purchasing livestock for purposes of slaughter or (2) slaughtering livestock for the sale, by such person or others, of meat or meat products.
"Livestock", cattle, calves, sheep, swine, horses, mules, goats and any other animal which can or may be used in and for the preparation of meat or meat products, excluding poultry.
"Packer", any person engaged in the business of slaughtering, or of manufacturing or preparing meat or meat products for sale, either by such person or others; or of manufacturing or preparing livestock products for sale by such person or others.
"Stockyard", any place, establishment or facility conducted or operated for compensation or profit as a public market, consisting of pens, or other enclosures, and their appurtenances, for the handling, keeping and holding of livestock for the purpose of sale or shipment.
"Humane method", a method whereby the animal is rendered insensible to pain by mechanical, electrical, chemical or other means that is rapid and effective, before being shackled, hoisted, thrown, cast or cut; or a method of slaughtering, including handling and other preparation for slaughtering, required by or used in connection with the ritual requirements of the Jewish faith or of any other religious faith, 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, § 139C