Mass. Gen. Laws ch. 98 § 56B
Whoever being engaged in the business of selling prepackaged meat, poultry or edible fish at retail refuses or neglects to provide each outlet where said products are sold with a computing scale or refuses to reweigh a prepackaged item of meat, poultry or edible fish in the presence of a prospective purchaser, when so requested, shall be punished by a fine of not less than one hundred dollars or shall be subject to a civil citation as provided in section 29A.
For the purpose of this section, a computing scale shall be deemed one that indicates the money values of a commodity weighed at predetermined unit prices throughout all or part of the weighing range of the scale.
For the purpose of this section, prepackaged meat, poultry, or edible fish shall not include (a) canned meat, poultry or fish; (b) prepackaged cold cuts or other processed meats; or (c) poultry or fish packaged off the premises and labelled with the net quantity of contents.
Mass. Gen. Laws ch. 98, § 56B