jen, i put a shim on top in the fall well before cold weather hits. i also heft my hives throughout cold weather to help me determine if i need to open them to add feed, but also know what is in there going into winter months.
any feed added, temp dependent. prefer 50 degrees to remove the insulated outer cover and just tip the inner cover enough to shove a winter patty in....i don't use fondant, but same concept applies. done very quickly.
at 40 degrees, i get in and get out. i don't take the inner cover completely off, just lift it enough to get the feed in. that's it.
below that, emergency, the inner cover is pried and tilted back and feed shoved in quickly. haven't had to do this for some time, but it can be done.
"my bees are often out and about between 40-45 degrees, so I figures that they are pretty acclimated to these very cool days."if they are jen, they are taking cleansing flights, or the cluster has been disturbed. bees cluster at about 54-57degrees F. you don't want to disturb this cluster, and want to minimize any disturbance. bees will fly at all temps in defense of the hive, so try to minimize this as best you can, temperature, and prying off the outer/inner cover......be gentle.
with your shim on now, going forward, if you had to open hives that seem light in less desirable temperatures, below 50df, get in, get out, no time for pix.........
i guess what i am trying to say, think of this in terms of your front door or whatever door visitors use to enter your heated home. someone comes to visit, (welcome or not.....
) and leaves the door open. heat escapes. if set at a temp, a furnace works to recover the heat loss from that room to bring it back to a certain temp......
and so the bees work to heat themselves in the cluster.
hope this made sense?
"my original question was about the third hive, and having the bees all the way up and thru the top super and milling around on the top of the frames. Was wondering if this is a sign of them doing the chimney thing?" as far as the 3rd hive and the bees being already in the top? my guess is, there is nothing in the bottom deep, or if there is, maybe in the very outside frames. bees will move up and bees will cluster, or will extend a cluster to the tops of hive frames. your weather is different than mine. if you have frames of honey on either side of that cluster, your weather will most likely allow them to move from side to side to utilize those honey stores. if there are no honey stores on either side of them, putting the fondant on is good. whether there are honey stores on either side, placing fondant on or some type of winter feed is always a plus if needed.......