Minecraft abandoned village

I was just coming home from exploring (pe) and I stumbled upon anot abandoned village. Like it was covered in cobwebs and mossy cobblestone. Doors were gone and it was deserted, I couldn't find animals, zombies/ zombie villagers. It was a ghost town. Any information on what this is or if it's natural?

As of Pocket Edition 0.15.0, Villages have a 5% chance to spawn as what is known as a Zombie Village. In this mode, Villages will spawn with moss stone and cobblestone as noted, and Zombie villagers will be present.

Your case of Zombie Villagers not spawning is likely a result of you either being in Peaceful mode, or just bad luck.