Just to get some things cleard up -
Several pokemon eat each other (bird types often eat bug types), its just the natural food chain.
People eat farfetch'd and slowpoke tails.
In the anime, animals also exist in the pokemon world that people eat (fish i can remember seeing off the top of my head). Ash also mentions eating a hamburger, so we can safely assume cows are present. I think if they were made from miltanks they would be called something else, as hamburgers imply COW, and miltank and cow are two completely creatures.
Since in the real world people can eat virtually any animal (people eat alligators and domestic dogs), i would assume, in the pokemon world, people could eat any pokemon they please, save for legendaries. Making an educated guess, we can assume Miltank, Torchic, Bird-Pokemon eggs, Ducklet/Psyduck, Grumpig/Tepig, Buneary/Lopunny, would be very popular delicacies.
My biggest question is, how would they capture the pokemon if bullets probably wouldn't effect most, and they would no doubt defend themsleves, possibly killing the person in the process? So i think we can conclude catching pokemon for food would be a very dangerous job.