I have 3 hives and two are strong and healthy but the 3rd just does not seem to be thriving. They lost their queen in the spring and now have a new one but their numbers are not growing, they forage sporadically, are not drawing out comb, and have very little brood. Today I was inspecting the hive and noticed that some of the bees seem to be an odd colour - sort of a light grey. The whole hive was, in general, rather quiet and pathetic looking. The hive next to it which is the same age is bustling and happy, has lots of capped brood and is storing some serious amounts of honey. It is very frustrating. I thought earlier in the summer their new queen (which they made) was just a slow starter but now I am really getting worried. I saw her bustling about this morning so I know she is still in there. Any thoughts?