On the Offical Community Realm, witches are spawning in the wrong Biomes for example in a Tiga or Planes Biome and while Offical Community Realm does have some swampy areas they are rather small and sporadic. While players have found villages, the villages are so far from spawn that the likelihood of a villager being struck by lighting and coming to spawn of there own violation is highly unlikely.

"...witches now spawn naturally, though they are rarer than Endermen. Before this update, they could only be found in Witches' huts. They also spawn when a villager is struck with lightning. ."