After the discovery of “Shiny Pokémon code” in the 0.57.2 version of Pokémon GO, it has been confirmed that Shiny Pokémon are coming to Pokémon GO.
Shiny Pokémon are special variants of regular Pokémon models, colored differently than their originals. All Gen 1 and 2 Pokémon have Shiny variants.
How to find Shiny Pokémon in Pokémon GO
At this point, it is still not known how Shiny Pokémon will be obtained in Pokémon GO, but it is known they will be using the same models like regular Pokémon, but with different spawn animation and coloring.