My strongest 10 frame hive; one deep (9 5/8") and two westerns (7 5/8") has dwindled down to one western (7 5/8") chamber. Four weeks ago this hive was full of bees each frame covered??? The queen is laying in a softball size pattern on three frames now. No sign of disease. Did have several small hive beetles and the hive is in full sun. What could cause this?