I have two hives that are about 5 years old, and I have 3 hives that I just purchased in April and then a swarm from May. The 3 new hives and the swarm just had the 3rd boxes put on them. The 2 old hives seem like they are barely doing anything. The 2 old hives had 3 mediums on them for the winter and were still almost full when I checked them in March. Since then, I have only put one more box on and it seems like they are barely doing anything when compared to the 4 new hives. One of the old hives seems like the bee count is real low. Both old hives have brood in them. What should I bee checking for next time I open them up? I know both of them have really dark wax (dark brown, almost black). Not sure if that matters. Thanks for the help.