It shall be unlawful for any person, except those persons doing a general pork or beef packing business whose operations are under the supervision of the bureau of animal industry of the United States Department of Agriculture, to engage in the business or occupation of rendering, disposing of or the reducing of dead animals of any kind within the city, or to use the streets of the city for the purpose of conveying dead animals to the rendering or disposal plant without first having made application and having obtained a license therefor in the manner provided in this chapter. (Rev. Ord. 1540, Comp. 1941, p. L-4)