I've killed my bees.

[220]

A double deep nuc that has starved, my own fault I thought it felt a bit light 3 weeks ago but not wanting to open until we had a reasonable weather and timing with work meant it was today before I opened it. 
Looks like I was a week to late, all dead heads down in cells, no honey but lots of pollen. Did find 3 bees barely alive while shaking off the frames so I'm basing my week to late call on that.
I have another double deep nuc and a single that when I opened the bees were at the top of the frames. I'm a bit concerned for them now, I made up a couple of shims and had some dry sugar with me so placed a sheet of paper over half the frames and poured sugar on top.
Worried about my other 2 hives as well, a 8 frame double deep and a 8 frame deep with a ideal box on top. Both had what I thought was plenty of stores going into winter (top boxes full) but I'm not sure now. Didn't have any shims for the 8 frame hives so I put some sugar under the lid on the inner cover.
Both of these hives were very active late morning, lots of bees flying and on the front of the hive. This has me concerned as temp was still below 5c at the time although we had sunshine for 4-5hrs and it felt far warmer in the sun. Not sure if the activity was because they are light and out looking for food or simply because today was the best weather we have had after about 10 days of rain and overcast days.

Should I knock up some 8 frame shims and feed the same way I have with the nucs or will the bees go through the hole in the inner cover to get to the sugar if they need it?

Trying to work out why the nuc that has died out went through their stores so quickly. If anything it went into winter with more stores than the other double deep nuc. The only major difference was the one that is still alive I insulated with foam broccoli boxes along with the single deep nuc that is still alive and the dead nuc wasn't insulated.

I was also surprised by the number of bees in the dead nuc, I have shaken the dead bees from the frames into the bottom box and with frames removed it is half full. I am wondering if due to our mild autumn the queen didn't slow down early enough and they went into winter with more bees than needed.

I guess I have learnt a couple of things to take forward,
* insulation makes a difference
* if I think a hive is light act straight away

[Acebird]

As always the size of the physical hive is less important than what is in the hive.  The amount of stores should be proportionate to the size of the cluster.  What makes things a little squirrely is the weather / climate.  When the weather is above 50 and no nectar is available the hive needs more stores because they are active.  Secondly, if the colony jumps the gun and broods up sooner than it normally would you need a lot more stores.  If you feed you can't walk away because you could induce brooding sooner.
I doubt if insulating made any difference.

[220]

Have been reading my notes and going over what I did to starve this hive.
Think I know where I went wrong, I had another hive that lost the queen and numbers had really dwindled before I realised. Instead of letting them die out naturally or shaking them out I combined them with the nuc I lost.  This was done early April the other hives all looked to have sufficient stores and were still bringing in pollen and nectar so thought this hive would be right as well. Obviously the increase in numbers a light flow and a short window before winter wasn't enough time. I should have feed them heavily after the combine.

Another contributing factor may have been the Italian queen, cleaning up the frames I had 2 frames with 6" patches of capped brood, by my calculations they would have been laid around the winter solstice.

I feed sugar to all my remaining hives as a precaution, checked yesterday and one looks to have used most of it, 2 have showed a little interest and 1 is dumping it out the from door.

[Acebird]

Interesting ... You say this:

Instead of letting them die out naturally or shaking them out I combined them with the nuc I lost.

But then you conclude this:
 

I should have feed them heavily after the combine.

[220]

What I meant was if I didn't intend to feed I shouldn't of combined.
Looking back if I had let them die out and not combined there is a good chance the nuc I combined with would still be OK.

Given I did combine and they starved I can only conclude feeding heavily in the small window I had would of increased their chances of making it through winter. They may still have starved but their odds of making it would have been a little better.

I made a mistake in combining and then followed it with another bad call in not feeding, I'm sure they wont be the last I make.
As a newbie I found it hard to accept that letting bees die could be the best thing when my goal was getting as many bees through the coming winter as I could.

[Acebird]

220 you have to come to grips that all your bees will die.  Your goal is that they will die at a time that benefits you.