REV 27-0036
A firm asks a customer for this certificate, the buyer fills in and signs the form from the emailed link, and Sundry shows it signed and Verified by Sundry.

Poultry sold for use in producing poultry or poultry products for sale is exempt from Washington sales and use tax: chicks sold to an egg farm, breeder stock sold to a hatchery, birds sold to a grower who raises them for market. A hatchery selling to farmers is the typical seller. Birds bought as pets or for a family's own eggs and meat are taxable.
Form REV 27 0036 (revision 7/13/23), Section B line 4c: "Poultry used in the production or sale of poultry products." The instructions describe it as "the purchase of poultry for the use in the production for sale of poultry or poultry products." The signature block asks for Account ID (if applicable), type of entity, name of buyer, farm name, mailing address, authorized signature, date, title and phone number. By signing, the buyer states it qualifies, that it "must keep records to verify the exempt nature of the sale," and that misuse "will result in taxes due, applicable interest, and possible penalties." The form has no field for the seller's name. The buyer ticks single use or blanket; a blanket certificate stays valid while there is at least one sale within 12 months. Cannabis growers and producers cannot use the form.
WAC 458-20-210(10): sellers "must retain a copy of the exemption certificate or the data elements in their files." On the B&O side, farmers producing hatching eggs or poultry are exempt from B&O tax on sales of hatching eggs or poultry for use in the production for sale of poultry or poultry products (WAC 458-20-210(8)(d)(iii), citing RCW 82.04.410). Form REV 27 0036 says the seller "must retain the original of this certificate for their records" and must not send a copy to the Department, and: "A seller who accepts this completed certificate is relieved of the responsibility to collect retail sales or use tax unless the seller fraudulently fails to collect the tax or solicits the purchaser to participate in unlawfully claiming the exemption." The certificate does not expire while buyer and seller have at least one sale within twelve consecutive months; after a longer gap the seller must obtain a new form. WAC 458-20-210(10): "Without proper documentation, sellers are liable for payment of the retail sales tax on sales claimed as exempt." RCW 82.32.070(1) requires records to be kept for five years, and RCW 82.08.050(7)(a)-(b) gives the 90-day and 120-day windows for obtaining a fully completed certificate.