Publication 52, Hazardous, Restricted, and Perishable Mail > 5 Perishable Matter > 52 Animals > 523 Acceptance for Mailing
A mailpiece containing live animals that cannot reach its destination in a viable condition should not be accepted. Factors that can be taken into consideration in assessing the viability of a mailpiece containing live animals include: use of proper packaging methods that protect against suffocation and crushing during transport; expected time in transit; and extreme weather conditions that exceed the normal weather pattern along the transportation route.
This provision does not give Postal Service personnel the authority to refuse mailable animals that are properly packaged or to impose local black–out periods based on temperature conditions, heavy mail volumes, etc. Acceptance personnel must have reasonable justification to refuse a mailpiece. Before refusing any mailpiece that contains a mailable type of animal, acceptance personnel are to confer with the manager, business mail entry, at their district office or with the PCSC, as appropriate.
Animals mailed to the Republic of Palau, the Republic of the Marshall Islands, and the Federated States of Micronesia require a permit issued by the government of the destination country. See 642.