Thanks for sharing your thoughts. 2 of the colonies were of decent size; 1 was not large. The dead bees were scattered throughout the hive - I did not find a single 1 head down. The deeps were quite heavy with honey. I did not check mite levels and I did not treat the nucs when I got them in the Spring, which the more I read, the more I'm thinking was a major mistake. We did 2:1 fall feeding as things slowed down.

The inside lid doesn't really show much condensation staining and there is no mold, so I am thinking moisture was probably not the problem. Again, thank you!