All the hives are the same size, what I think of as a standard hive size, and are wood with metal roofs. The obsevation hive varies in that it has three doors that can be raised to view a cutout covered in plexiglass. Those doors are taped shut in the winter. All the hives are outdoors but the observation hive in near the entrance to the bee garden and the other 6 are up the hill toward the back. All our bees died during the winter in 2013 so the beekeeper brought new colonies last May. I don't know if the other 6 hives survived but the front hive was a flurry of activity last week.