An Act to Prevent Cruelty to Farm Animals, more commonly known as Question 3, was the third initiative on the 2016 Massachusetts ballot. The measure requires Massachusetts farmers to give chickens, pigs, and calves enough room to turn around, stand up, lie down, and fully extend their limbs. It also prohibits the sale of eggs or meat from animals raised in conditions that did not meet these standards.

In 2016, eleven other states had enacted laws against some of these forms of confinement, and California had a law prohibiting the sale of any eggs from chickens kept in small cages. The measure was supported by the Humane Society of the United States and its allies, and opposed by regional and national animal agriculture groups. Proponents argued that the initiative represented a modest animal welfare reform that would benefit food safety, while opponents rejected both claims and warned that the regulations would sharply increase the price of animal products, harming low-income Massachusetts residents.

The measure was overwhelmingly approved by voters, with 77.6% of votes in favor, becoming the broadest statute against farm animal confinement in the country. It took full effect on January 1, 2022.

Question 3 has been the subject of two legal challenges. The first, attempting to block it from the ballot for procedural reasons, was ruled against by the Massachusetts Supreme Judicial Court in July 2016. The second was filed with the U.S. Supreme Court by a coalition of agricultural states, claiming Question 3's provisions violated the dormant Commerce Clause; the Court declined to hear the case in January 2019.

Modern animal agriculture in the United States is dominated by indoor-housing systems in which animals are kept at very high densities, in order to maximize economic profit. These systems decrease land use requirements and increase feeding efficiency, but they restrict animals' movement, prevent animals from engaging in natural behaviors, and can lead to production-related diseases.

Three such systems have been the focus of most regulatory debate: battery cages for egg-laying hens, gestation crates for pregnant sows, and veal crates for male dairy calves. Battery cages are stacks of wire crates that contain one to eight or more hens, with each hen typically being allotted less space than a sheet of printer paper; according to U.S. Department of Agriculture estimates, this practice accounted for over 90% of commercial U.S. egg production in 2016. Gestation stalls are not much larger than the sows they confine, and were used by more than 80 percent of U.S. pork producers. In the dairy industry, both male and female calves are taken from cows within a few days of birth to maximize milk yields, and kept in crates that limit their movement and ability to interact with other calves.

In the decade before Massachusetts Question 3, a number of large American food chains, retailers, and animal agriculture corporations had voluntarily committed to plans phasing out the use of battery cages in egg production and gestation crates in pork production.

No federal legislation protects the welfare of U.S. farm animals except during transportation and slaughter, and poultry are excluded from the latter regulations. This lack of regulation has sometimes been attributed to the influence of agricultural interest groups at the federal level.