I'd agree with Finman, it looks like they couldn't quite reach the last of the fondant.
But there aren't many on the frame. Usually a starved colony will die quickly, and many will die with just their little backsides sticking out of the cells, which isn't what I see here. There are an awful lot of dead ones on the floor, though.
I'd normally put this down to nosema weakening the colony, probably over a period of weeks, to a state where it just can't move far enough to reach food, stores or anything. Although there's no obvious sign of dystentery, its absence isn't conclusive (especially if starvation is a factor), and only a microscope can really tell you if it's there.
Like many, I'm sceptical that bees do die of cold, as such, unless the colony is already too weak to survive. But then I live in a balmy borough of London, and it might be different in the chillier shires.