If you've been feeding and medicating 6 such hives since the Spring and 5 of them have died, I would be wondering if the bees are either sick with some serious disease or if perhaps you have over medicated or treated them to the point of toxicity. Too much treatment? Or is there some pesticide being applied in your area that might be poisoning the bees? 'Shaking' bees as you describe might be poisoned bees.
Originally Posted by bee luscious
And what do you mean by 'sprinkling some feed'? What kind of feed?
Do you have other hives as well, that are healthy?
The little bee returns with evening's gloom,
To join her comrades in the braided hive... -Tennyson