Mass. Gen. Laws ch. 128 § 51
The following words as used in section fifty-two to section sixty-three, inclusive, unless a different meaning is required by the context, or is specifically described, shall have the following meanings:
"Brand name", any word, name, symbol or device, or any combination thereof, identifying the commercial feed of a distributor or registrant and distinguishing it from that of others.
"Commercial feed", all materials except unmixed seed, whole or processed, when not adulterated within the meaning of section fifty-four which are distributed for use as feed or for mixture in feed; provided, that the commissioner by regulation may exempt from this definition, or from specific provisions of this act, commodities such as hay, straw, stover, silage, cobs, husks, hulls, and individual chemical compounds or substances when such commodities, compounds or substances are not inter-mixed with other materials, and are not adulterated within the meaning of said section fifty-four.
"Contract feeder", a person who is an independent contractor, feeds commercial feed to animals pursuant to a contract whereby such commercial feed is supplied, furnished, or otherwise provided to such person and whereby such person's remuneration is determined all or in part by feed consumption, mortality, profits, or amount, or quality of product.
"Customer-formula feed", commercial feed which consists of a mixture of the commercial feeds, or feed ingredients, each batch of which is manufactured according to the specific instructions of the final purchaser.
"Drug", any article intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease in animals other than man, and articles other than feed intended to affect the structure or any function of the animal body.
"Mineral feed", a commercial feed intended to supply primarily mineral elements or inorganic nutrients.
"Official sample", a sample of feed taken by the commissioner or his agent in accordance with the provisions of section fifty-eight D.
"Per cent or percentage", the per cent by weight.
"Pet food", any commercial feed prepared and distributed for consumption by pets.
"Product name", the name of the commercial feed which identifies it as to kind, class, or specific use.
Mass. Gen. Laws ch. 128, § 51