When you refer to this a your mother hive, is this the one that threw it's first swarm 2 or 3 weeks ago? If so, multiple eggs in one cell is something you often see with a new queen when she first begins laying. It often takes them a week or so to get things sorted out so to speak. The frame in the picture looks to me like comb with nectar and bee bread, (and a few larvae and eggs in the the small drone cell patch).
Why your hives seem to be throwing swarms left, right, and center, is baffling to me. When you are going through them you should be seeing signs.