Pokémon Go Egg Chart For Hatching 2km, 5km And 10km Eggs banner300x250
At this point, there still hasn't been enough data collected from Pokmon Go players to determine for certain the chances of hatching a particular Pokmon. However, our purely anecdotal experience suggests certain Pokmon almost certainly do have higher or lower chances to hatch from Eggs.
At launch we saw plenty of disgruntled players drawing attention to the frequency of Eevees in 10km Eggs, for instance, compared to relatively few celebrating their second or third Snorlax.
However, this specific case should be a thing of the past thanks to Eevee's demotion to 5km eggs in an Autumn update, which could actually this tier more useful, since Vaporeon - one of Eevee's three evolutions - appears to be one of the best Pokmon in the game currently, with the added benefit of freeing up 10km Eggs for more rarer creatures.
Likewise, 2km Eggs are also more useful than you'd expect, thanks to the fact that starter Pokmon can be acquired for the fairly low-investment. It's worth noting that at this point it's currently unclear just what the probability is of landing yourself a Bulbasaur, Charmander, Squirtle, or Pikachu from hatching Eggs. However, with the starters being relatively scarce in the wild - and relatively demanding in terms of Candy to evolve - if you want to land yourself a Venusaur, Charizard, Blastoise or Raichu, focusing your efforts on the 2km Eggs is likely your best bet.
Source : http://www.eurogamer.net/articles/2017-02-22-pokemon-go-eggs-chart-hatching-2km-5km-10km-eggs