Section 151. (a) The mayor of each city and the board of selectmen of each town shall annually designate an animal control officer, who may be a police officer or constable. The mayor or board of selectmen shall immediately submit to the commissioner the names, addresses and dates of hire of such animal control officers. Except as provided in this section, if a city or town shall fail to make such appointment, the commissioner shall appoint an animal control officer for that city or town. An animal control officer who fails to comply with the terms of such officer's warrant shall immediately be removed from office by the mayor or board of selectmen and notice of the removal shall immediately be given to the commissioner. Animal control officers shall have completed, under the supervision of a veterinarian registered under section 55 or 56C of chapter 112, a course of instruction in humane techniques for the execution of animals before euthanizing an animal. Before euthanizing or giving or turning over to another a dog or cat in the officer's possession, an animal control officer shall first examine the animal for the presence of a microchip or tattoo, check the description of the animal against descriptions within the city or town relative to the species of animal licensed or registered in the municipality in order to verify the identity of the animal and to provide notice to the owner of the animal before the animal is euthanized, given away or turned over to another. Bills for such services shall be approved by the mayor of the city or the board of selectmen of the town in which the dogs or cats are kept or euthanized and shall be paid by that city or town. An animal control officer appointed under this section shall also attend to all complaints or other matters pertaining to animals, as prescribed by the officer's respective city or town, in addition to the duties imposed upon the officer by the officer's warrant, and shall be paid for such services by the town or city treasurer upon bills approved by the mayor or board of selectmen. The mayor of a city or the board of selectmen of a town may, instead of appointing an animal control officer, enter into a contract with a domestic charitable corporation incorporated exclusively for the purpose of protecting animals from cruelty, neglect or abuse to perform the duties required of an animal control officer. In that case, the payments to the corporation under the terms of the contract shall be in full for all services rendered by it in that capacity.

(b) An animal control officer shall not be a licensed animal dealer registered with the United States Department of Agriculture. An animal control officer shall not give, sell or turn over any animal which may come into the officer's custody to a business or institution licensed or registered as a research facility or animal dealer with the United States Department of Agriculture either privately or in the course of carrying out the officer's official assignments as an agent for the officer's municipality. A municipality shall not give, sell or turn over an animal which may come into its custody to any business or institution licensed or registered as a research facility or animal dealer with the United States Department of Agriculture. Whoever violates this subsection shall be punished by a fine of not more than $1,000.