Slang originated from the Vietnam War, meaning human flesh made for consumption.
Guy A: Yo I'm hungry. Want to eat some of my mom's meatloaf?
Guy B: Fuck fuckin' no! That's stuff is worse than vietnamese chicken, and it looks worse too. I'd eat rather your mom's vagina. Fuck.
Guy A:(Cries Quietly)
A code name for meat made out of people. Derived from the hardcore stuff that happened in the Vietnam War.
Guy A "Fuck you. Wanna go?"
Guy B "Oh yeah? I'll beat you so bad you'll look like a piece of vietnamese chicken."