Effective October 19, 2026, the Postal Service™ amended Chapter 5 of Publication 52, Hazardous, Restricted, and Perishable Mail (Pub 52) to prohibit the reuse of fiberboard containers transporting live animals and requires individual addressing and sequential numbering for multiple-container shipments when bound together in a single shipment. Additionally, the Postal Service recommends that mailers write the recipient’s name and address directly on the packaging of adult bird shipments in case the shipping label becomes detached from the packaging.
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Publication 52 — Hazardous, Restricted, and Perishable Mail
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5 Perishable Matter
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52 Animals
521 General Requirements
[Add a note after item c(3) to read as follows:]
Note: Due to the high likelihood of degradation during transportation, fiberboard containers must not be reused for live animal shipments.
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522 Packaging and Markings
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522.1 Container Construction
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***When multiple containers are strapped together, a single shipping label should be applied, but each container must have its own address label. Additionally, the containers must be numbered sequentially (e.g., “1 of 5,” “2 of 5,” etc.) to help ensure proper handling if they become separated during transit.***
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526 Mailable Live Animals
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526.4 Adult Birds
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526.42 Mailability Requirements
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[Add a note after item f. to read as follows:]
Note: It is recommended that the name and address of the recipient also be written on the packaging in addition to the shipping label.
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Appendix C
USPS Packaging Instructions for Mailable Hazardous Materials
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USPS Packaging Instruction 10D
Adult Bird Boxes
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Marking
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[Add a bullet point before the last sentence of this section and align with the previous bullets, to read as follows:]
n Directional arrows indicating “up” position (on at least two sides of the container).
[Add a note after the last bullet to read as follows:]
Note: It is recommended to write the name and address of the recipient directly on the package in case the shipping label becomes detached during shipment.
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Although effective immediately, the Postal Service™ will incorporate this revision into the next update of the Pub 52, which is available via Postal Explorer® at pe.usps.com.
— Product Classification,
Product Solutions, 11-12-26
