N.Y. AGM Law § 111

§ 111. Identification of dogs. 1. Each dog licensed pursuant to\nsubdivision one of section one hundred nine of this article shall be\nassigned, at the time the dog is first licensed, a municipal\nidentification number. Such identification number shall be carried by\nthe dog on an identification tag which shall be affixed to a collar on\nthe dog at all times, provided that a municipality may exempt dogs\nparticipating in a dog show during such participation.\n 2. No tag carrying an identification number shall be affixed to the\ncollar of any dog other than the one to which that number has been\nassigned.\n 3. A municipality offering a purebred license may provide a licensee,\nat his or her expense, any number of tags imprinted with the same number\nas the purebred license. One such tag shall be affixed to the collar of\neach dog harbored pursuant to the purebred license at all times,\nprovided that municipalities may exempt dogs participating in a dog show\nduring such participation. Such a tag shall be affixed only to the\ncollar of a dog owned by the holder of the purebred license and harbored\non his premises.\n 4. A municipality offering a license for any guide dog, service dog,\nhearing dog, therapy dog or detection dog may issue a special tag for\nidentifying such dog, provided that such tag shall be in addition to the\nidentification tag required by subdivision one of this section. The\nmunicipality may prescribe the shape, size, color, and form of imprint\nof the tag which shall be a different color and shape than the standard\nidentification tag. Upon application, the commissioner shall furnish\nsuch tags without payment of a fee.\n