While me and my friend are out collecting slime balls, a fair distance from our houses and villagers, we noticed an unusually large number of zombie villagers, the vast majority which had professions. Later, when we returned to check on what was previously a 'village' (a box containing several villagers with great trades where cats refuse to spawn), they where all gone except for one that was a zombie. There was no way the zombies could have spawned inside the villager box as it was fully lit and they couldn't have gotten in through the doorway as there where multiple fence-gates that we always keep shut and a door that was also closed. I understand that zombie sieges can occur in villages, regardless of the light level but the villager box was not classed as a village and anyway, how did our villagers find themselves all the way over to us, a good couple of hundred blocks away.