Directly to you from Twitter:
Until July 24, Pichu wearing Ash's famous hat can be hatched from Eggs. Get cracking, Trainers! pic.twitter.com/ILSDG6KzrN— Pokémon GO (@PokemonGoApp) July 15, 2017
…Wanna play? Buy a 3DS.
That being said, click on Pokémon Go for everything you need to know about the game. 😀