12-12-2016, 11:12 PM
The easiest way force witch spawns is to have lightning strike close to villagers which is still a challenge in of it's own. I guess you could build and area like a villager farm but open on top to allow lightning to strike inside and added bonus... enough villagers and it can become and iron/witch farm or an auto witch farm when the iron gollums kill the witches.
The way Minecraft was meant to be played.