I agreed to move remove a feral beehive that was in a bush, established for a couple months. First time I showed up, someone has squirted the bees with a hose for an hour and one side of the hive was rather wet. Showed up a couple days later, I dismantled the comb, discarded the bits without brood on it and strapped down the bits with brood on frames with rubberbands. The job took longer than I figured, it was a few hours past sunset and thousands of bees was still outside the hive. I tried to encourage them to enter the hive, by putting a lot of lemon grass oil in there, maybe 50 drops, I've learned since that this was a mistake.
So I left, and came back the following day. I made another mistake because I didn't provide shade from the sun, it's summer here in Australia and the hive probably got quite hot. When I showed up the following evening, there was less than a thousand bees in the hive, the large majority of them swarmed to a tree just 10-15 meters away. I parked my car underneath, put a cabinet on top, placed the hive on top of the cabinet and scooped, and shacked the bees into the hive. I then drove them to the new site and dropped them off.
I returned eight days later. The owner of the property told me that he went out the back about 20 hours after I dropped off the bees, and there were many thousands of dead bees outside the hives. The two hives sharing the stand didn't seem to have lost any bees, so it seems they were mostly all from the swarm that I captured.
The hive had some sugar ants, moths, wasps, wax moth and a small, green/brown beetle with a little black dot roaming about inside, about the size of a small hive beetle(tried to take a photo of it but it hid with some comb and I didn't see it again). There was a number of baby bees that tried to hatch from brood comb, failed and died. There was maybe a few hundred bees left. I saw some eggs in one section of comb, but I didn't see a queen.
Here's some photos:
https://imgur.com/a/Fywu7I basically took a photo of every part of the hive, some frames got photos at different angles.
I wasn't sure what to do. I thought about leaving them there, but figured the chances of them surviving was less than 1%. I thought about merging them with another hive, but considering how many actual bees were here, and I figured there was a possibility that they had some disease or pest, I didn't think it was worth it, so I just brought them back home with me.
What potential reasons are there for the bees dying? What could have caused the brood to be unable to hatch? What would have you guys done differently? Could have that little green/brown bug be some sort of pest that contributed to their decline, or was it likely just a common bug? Was the eggs that were laid, likely from before the hive was moved?