I live in the South Atlanta, GA area where we had a relatively mild to cold winter. The history on my hive is that I am a one year new beekeeper. Last March, 2017 I bought a mated Queen with her bees. The bees were purchased fairly local, mid Southwest, SC. I initially housed them in a two chamber hive. I located the hive in my back yard where the hive get direct sun light 3/4 of the day. It is located on the south side of a wood privacy fence, blocking north winds. The new bees were so prolific, the hive split two times last spring. After the second split, I added a third chamber. The hive did very well after adding the third chamber. After the last nectar flow last year, I checked the hive to see what the honey storage looked like for the winter. The bottom brood chamber had a good storage of eggs, cone, and live population. The center chamber was used by the bees to store honey, pollen, and some brood eggs. There was more than enough honey stored, about 30lbs. Two weeks ago I noticed just a little activity on the outside of the hive. I could hear the hive humming on the inside, so I was under the opinion the hive was doing good. This past weekend I noticed no activity at all. I could not hear any humming inside the hive. I went out today to inspect the hive and found that every bee was dead. There was more than enough honey stored to last the rest of the winter, about 10lbs remaining. I did a search for the queen but had no luck in finding her. I could have easily missed her. I cleaned the hive out and left the cone and honey in the hive. I closed up the entry ways to keep unwanted visitors out. While I was cleaning, I had one honeybee visiting while cleaning. It would not go into the hive. Should I close it up or keep it open? Does anybody think the queen and her bees left the hive? Anybody have any ideas why the hive died on me.