It isn't hacked, I bred it myself. It shows it as legit now though, I've rechecked after leveling it a few times not sure that had anything to do with it.
Ferrothorns move Spike is listed as Hacked/event which I don't think it should.
Take a look here, http://bulbapedia.bulbagarden.net/wiki/Ferrothorn_(Pok%C3%A9mon)#By_breeding
Its listed as a breeding move.