At inspection today, two of my five hives had slow-moving, relatively inactive bees. Last week I extracted honey and removed supers. The two brood boxes have a lot of bees but there is plenty of space. There are stores but only patchy and only on one or two frames. I plan to feed this evening.

Should I assume that the bees were so short of stores and that this is why they have slowed?

This prompts me to ask if anyone has advice on feeding, other than the usual "fondant in spring and a "good feed of syrup in late summer".