Foreign born workers comprise 37% of meat processing workers. That compares to 17% of all workers being foreign-born. Generally speaking, it appears that white Americans are under-represented in meat processing by about 2/3rds and foreign born are over-represented by double.

The bulk of foreign-born meat processing workers are from Mexico (46%) and other Latin American countries (about 20%). Other regions well represented are Asian 12% (Burma, China and Vietnam) and Africa (9%).

Poultry processing is concentrated in the South (largest numbers in Georgia and Arkansas) while processing of other meat is concentrated in the Plains states (largest s in Nebraska and Iowa).

Also here and  here.