The latest update to Pokémon Go adds in seven new Pokémon from the series' second generation (Gold and Silver) including Pichu and Togepi. All seven new creatures are what's referred to as "baby Pokémon" and can only be hatched from eggs.
Igglybuff and Cleffa hatch from 2km eggs, Pichu and Togepi hatch from 5km eggs, and Magby, Elekid and Smoochum hatch from 10km eggs. Of course, hatching an egg doesn't guarantee you'll get a new Pokémon, there's still a high chance of getting one of original 150.
Eggs are randomly given out at Poké Stops, and are hatched using incubators. You get an infinite use incubator when you start Pokémon Go, and occasionally pick up perishable incubators as you level up. Eggs can be hatched by going to your "Pokémon" tab within the game. Select the "Egg" menu, and then pick the egg you want to hatch and pop it in an incubator. Once you pop an egg in an incubator, it will hatch after you walk the designated number of kilometres.
You'll also run into a Christmas-themed Pikachu wearing a Santa hat when hunting Pokémon. These are catchable until December 29. When it evolves, the Raichu will keep the hat.
The news follows a recent announcement where Sprint confirmed that over 10,500 stores around the country will be turned into Poké Stops and Gyms.