Common Pokémon Replaced!
Looks like common Pokémon that spawn will be reduced and replaced with others! Great news, the Pokémon Go app gets better and better! Also, Pidgey and Rattata no longer hatch from eggs! Eevee hatch at 5km eggs only!
Professor Willow has discovered that you may encounter other Pokémon where Pidgey, Rattata, and Zubat were previously more commonly found.
— Pokémon GO (@PokemonGoApp) November 3, 2016