Indeed, they stay busy! I check on mine morning and night (through the window) and they do quite a bit over night. I put 1L of syrup in the hive around 9pm last night. In the morning it was gone (the syrup not the jar)!
They didn't seem to be fanning as that's what I thought they may have been doing . They look like they was trying to block the entrance off . Don't know thought first time I had every looked at them in them hours .Vote to recycle!!
Even though it is 60 degrees out side the hive may be over heated. All that sugar makes a lot of heat. Look closer if you can and see if they are fanning.