Hey Clem, Welcome to the forum! I'm a first year beek (Jun) so please ignore the rest of this post ;)
Several things to take into consideration in addition to what's already been mentioned. Small Hive Beetles, Low lying areas (moisture), neighbors, animals (cows, goats, ect), and the such. Also some folks may kick them over because they don't like them. I have one hive so I've really nothing to compare it to.
When I first got my bees I put them in a place where they got 3 or 4 hours of morning sun and had shade the rest of the day. I had a problem with small hive beetles and they weren't building up real fast. I got them after the main flow so that may account for the slow (in my mind) build up. I moved them probably 30 or 40 feet straight forward into more direct sunlight. It seem to help. I'm told SHB's like the shade. I got a IPK beetle trap (oil pan) and that took care of the SHBs. They seem to do better in the sun but I really can't say for sure.