With Ditto being released into the wild, Niantic's comments are
Ditto has been known to disguise itself as other Pokémon, so keep an eye out, some Pokémon may actually be Ditto, and when you capture them, there’s a chance that Ditto will reveal itself. If you do encounter a Pokémon that is Ditto in disguise, the Pokémon in that specific encounter will also reveal itself as Ditto for other Trainers.
While Niantic only mentioned Ditto being disgused in the wild as other Pokémon, it is possible to hatch a Ditto?