9 C.F.R. § 71.13
All persons and corporations having control of the interstate transportation of livestock or poultry shall, when directed by an APHIS inspector so to do, stop the same in transit for inspection, and if any of such poultry or other animals are found upon such inspection to be infected with any contagious, infectious, or communicable disease or to have been exposed to such infection, the person or corporation having control of the transportation of such poultry or other animals shall, upon receipt of an order from an APHIS representative so to do, cease the carriage, transportation, or moving of such poultry or other animals unless such carriage, transportation, or moving can be accomplished in accordance with the regulations in this subchapter governing the interstate movement of poultry or other animals infected with or which have been exposed to the infection of such disease, and in all cases after the discovery of such infection or exposure thereto such poultry or other animals shall be handled in accordance with such regulations.
9 C.F.R. §71.13