Some states are “open range” or a “fence out” states, meaning that a livestock owner does not have a legal duty to prevent animals from getting onto the roadway. But some state legislatures have enacted statutes known as "stock laws" that modify the common law (rules contained in court opinions written by judges) and prohibit owners from allowing animals to run at large.
Massachusetts is not an 'open range' or 'fence out' state. Instead, it requires livestock owners to prevent their animals from roaming at large. Under Massachusetts General Laws, specifically Part I, Title XIX, Chapter 128, Section 22, it is the responsibility of the owner to keep their animals from straying onto public ways and other people's property. Failure to do so can result in the animals being impounded and fines for the owner. Additionally, the owner may be liable for any damage caused by the animals while they are at large. This reflects a 'fence in' policy, where the burden is on the livestock owner to contain their animals within their property boundaries.