My top bar hive has gotten pretty crowded and this weekend the workers were kicking out drones left and right. Is that normal for this time of the year in North Carolina?

Also, the drones all just crawled around on the ground and eventually died. They appeared to be healthy but none of them could fly. Is it possible that they were just old? If there was some kind of disease or mites I wouldn't think it would be limited to just drones.

Thanks for your input.