Can You Tell If A Pokemon Is Hacked?

Hackers often produce Pokémon with shiny appearances, Pokémon with Pokérus, level 100 Pokémon with six flawless IVs, and movesets designed for competitive play. If you get any of these in an unexpected exchange, it is quite likely that it has been hacked. On the other side, it's quite probable that any Pokémon with a level one has already been bred and sold off.