Apparently, the heads aren’t the only parts of the body that Dodrio has three of. It has three sets of hearts and lungs as well, so it is capable of running long distances without rest. An odd species that is rarely found. The three heads respectively represent joy, sadness, and anger. An enemy that takes its eyes off any of the three heads--even for a second--will get pecked severely.
Pokédex entry #85
dodrio in Pokémon GO
It's possible to hatch dodrio from an egg?
No, dodrio can't be hatched.
Which are dodrio’s strengths and weaknesses?
dodrio is a flying and normal type Pokémon. flying type pokémons are strong against grass, fighting, bug pokémons but weak against electric, rock pokémons. normal type pokémons but weak against rock pokémons. They are not affected by ghost type pokémons.