https://www.eater.com/2018/12/11/18136019/costco-rotisserie-...
"At the center of the move is the company’s $4.99 rotisserie chicken. In 2014, Costco reported selling 78 million of these processed, four-pound birds a year. In order to guarantee a steady supply and maintain the price, Costco fixed its eye on Nebraska as the best place to start raising and processing its own supply of chickens, and “break free of the monopoly” held by companies such as Tyson and Pilgrim’s Pride, much like it did for sausage and hotdogs with its Kirkland plant in Tracy, California."
Store brand products are almost invariably made by manufacturers that have their own, non-store brands. Retailers aren't investing in buying production facilities for every kind of product they want a store brand for, they are paying manufacturers in the industry to make a store brand, which may or may not be distinct (aside from packaging) from products sold under non-store brands.
I’ve heard toilet paper is regional.
Probably a lot of other products, and I somehow think their dog food might be.
I don't care who actually made it, as long as it does what it says it does
The CNN article sort of side steps the issue, but does consistently call Kirklnad Signature a “brand” as opposed to “product line” or the like.
They buy enough quantity, put there own label on it.
https://www.certapet.com/kirkland-dog-food/