Because there is no land within the Borough of Lewistown to accommodate agricultural or farming uses or uses or features customarily incident thereto, and because of the existent residential, commercial, manufacturing and industrial development within the Borough of Lewistown, no chickens, ducks, pigeons or other fowl and no cows, goats, horses, pigs, rabbits (other than pet rabbits not to exceed two) or other livestock shall be kept or grazed in any Residential District, Commercial District or Manufacturing and Industrial District.