Minecraft wiki entry for Village_chaining, associated text: Before 1.8, the older a village is the more eligible it is to merge with a new village. Consequently, village chaining back then primarily used the merging range to prevent villages from merging initially. After 1.8, however, the nearer a village to a door the more eligible it is to merge with the door. If multiple villages have the same distance between their centers and a door, the door will prefer the older village more. This makes village chaining tougher, but also much more predictable, allowing a village to extend from a far spot to overlapping with a preexisting village. It also doesn't break chained villages from older versions as long as it is kept loaded, but old reset mechanisms no longer work.