So, I did a frame by frame inspection of all my hives yesterday. This morning I decided to put a box of 1/2 frames in one of the stronger ones - which involved sorting frame by frame through the box again to get it arranged so that the queen would lay the minis full of brood asap. Anyway, in less than 24 hours I'm certain they have brought in a super and a half (8 frame medium) full of nectar and pollen. The conditions are perfect, and maple is in full bloom. Woo Hoo!