How long does it take to build a hut on virtual villagers 3 the secret city?

That really all depends on how many people are working on the hut and the level of builder they are. More villagers working on it make the building go a lot faster. When I had about six or so working on a hut, they were done overnight. Also, if it's like the scientists (Master Scientists bring in more tech points), a master builder should build faster. Not 100% sure on that part. Also, if a villager is not a trainee builder, yet, they are likely to wander away if you set them to the task. You have to keep setting them to the task until they start building up some skill (set their preference to build to help). The more skill, the more likely they are to stay on task.