"Why is Natu in 5km eggs?"

#PokemonGO: http://ift.tt/2o13P8F seems like a waste, considering that Natu is the gen 2 verion of Spearow. Why is it in eggs at all, im not sure if its because of the biome that I am in but I see them everywhere. If its only my biome and in others they are more uncommon/rare that I can accept them being in 2km eggs but definitely not 5km. via /r/pokemongo http://ift.tt/2mMCAgP