It's a culmination of things: supply shortages, people stocking up, holidays, the fact that a lot of meat is processed internationally overseas as opposed to here in country
Some of the largest meat processing plants are in fact owned by Chinese companies.
Smithfield is one, the company that owns them also owns many other brands you'll notice.
Anyway, Smithfield also owns:
Smithfield
Eckrich
Nathan's (the hot dog people)
Farmer John
Farmland
Armour
Carando
Cook's (the ham people)
Curly's
Gwaltney
Healthy Ones
John Morrell (mostly in Canada)
Kretschmar
Margherita
Smithfield Culinary (commercial arm, like Sysco Foods)
https://www.smithfieldfoods.com/Our-Brands
This consolidation of food companies has been going on since the 90's when they repealed Glass-Stegall and made it possible for banks to make investments and they started buying up these brands on hostile debt takeovers and making these HUGE conglomerates. The Smithfield deal to an off-shore holding company never should have happened. Should have been stopped due to national security.
Anyway, WH Group owns WAY more than that:
http://www.wh-group.com/html/bp.php
In addition to those American brands, they also own these brands:
Patrick Cudahy
Pure Farms
American Farms
Cracker Barrel Old Country Store
The Cumberland Gap Provisions Company
Farmers Hickory Brand
Higueral
La Abuelita
La Bella
Maple River Brand
Marca El Rey
Mosey's
Oeco
The Peanut Shop of Williamsburg
Peyton's
Rath Black Hawk
Schickhaus
Shenson
Stefano Foods
Sterling
Sunnyland
Belinki
Morliny
Mazury Elk
Krakus
Elit
Yano
Veri
Plin De Carne by Elit
Premia
Promo
Pizzaro
Csabahus
Finonimo
Kaiser
Mecom
Schneiber (processed/deli meats)
Shuanghui