Could be that the colony has back filled the brood nest with honey/nectar and pollen. What are you seeing in the comb that doesn't have brood?

 

The broodless comb is the back of the hive and it is completely empty. The brood that is there is in the brood area at the front of the hive but there are far fewer brood combs and bees than I had less than two weeks ago.

 

When the hive is booming you can miss queen cells because the bees will cover the cells. Most likely the hive swarmed so you got a brood break a new queen and a hive that won't eat themselves to starvation because you have less bees. Would have been nice if you could have caught the swarm I've caught 2 of mine this year.

 

The hive was booming, but still had plenty of space. There was comb filling 3/4 of the hive with plenty of space for them to expand. And, I didn't find any hatched out queen cells when I inspected today. I'm not ruling out a swarm, and I don't know what other explanation there would be. It just seems strange for this time of year. I just started keeping bees this year, so I am still learning. This hive swarmed once this year in late spring. I noticed the swarm cells too late and my split didn't work out. I guess maybe my queen just reproduces like crazy. I will have to pay better attention to this hive next year and maybe get a couple splits out of her. And I'm pretty sure my old queen stayed with the hive. When I saw her she was huge, plump and in great health.

 

Just because you have some space in a hive doesn't mean they will use it befor they swarm. You found a queen and brood so they had plenty of time to remove the remnants of any queen cells. And yes bees will swarm any time of the year and don't let any one tell you different .

 

Varroa mites can cause rapid collapse of strong hives, have you checked for them at all with a sugar roll or alcohol wash? First year hive, they probably not that bad, but it is a possibility.

 

Do they have honey stores and how much? Again I don't know your location. You need to give more detail as to what you are seeing on and in the combs? Could be a number of things going on with your colony as others have mentioned.

 

As of now there are no honey stores. Most of the comb is empty, but they look to be filling back up with brood already. I live in south central Pennsylvania. We still have a good number of flowers around, and my other TBH is beginning to store honey, so I don't think there is a lack of nectar. I have not checked for mites, but with how quickly the bees were depleted and the info you guys have given me, I don't think it can be anything but a swarm. At least I have a healthy queen that is laying. I had a lang deep with comb from my failed split in case of a swarm, but it became infested with wax moths, so I burned all but the box after shaking the larvae out for my chickens.

 

A queen does naturally take a brood break during the fall dearth. Once the dearth breaks, she'll start laying the eggs which will become your long-lived winter bees. Once a number of foragers are available, the hive should start storing nectar like crazy. If not, take some honey from another hive (your own is preferable) to feed back to the lighter hive. I never feed sugar syrup anymore - it's not natural bee food. Honey is. So I source local, real honey through our beekeeping group to feed back to my hives if I run out.
My first year hives, I leave all stores of honey for them to use through the winter. Come spring flow (when dandelions bloom), then I take a few bars for our use. And only then.
Good luck...keep watching - a laying queen is a good sign!

 

Taking a guess that you have a fall flow which is good but i would still feed this colony as you say they have no stores. it will help them brood up.

 

It is possible that your colony was a little drone-heavy and now that they are gone the hive seems empty.

 

I would like to think that is the case, but I don't think so. I had a lot of capped brood, probably 7-8 full combs. Not many drone cells on them. All hatched out and looked great. Now I have half the bees I had before.