After my first package of bees died this spring (loss of queen, didn't realize it soon enough), I got a swarm about 3 weeks ago. On the advice of the guy who gave them to me, I began feeding them. Everyting seemed fine until tonite. I have the cover lifted for vetilation and the feeder hidden inside of a hive body. I noticed what seemed to be a lot of activity late today, centered around bees flying in and out from under the cover. Normally by this time at night they have settled down, but there is still and enormous amount of acitvity going in and out of the top hive body with the feeder inside ( I have a ventilation hole drilled underneath the hand hold). I just spent 15 minutes watching from about 10 feet away, but can see no fighting, and no additional dead bees in front of the hive. Should I have cause for concern? There is a cluster of bees at the hive opening, but they do not seem agitated in the least bit.
I don't like the idea of a feeder near any entrance. It leads to robbing. The other problem is when the feeder runs out they may rob all the honey.
If there is a lot more activity than normal you may have robbers. The bees may have just accepted the overwelming numbers and are just letting them rob. Since you need ventilation, I'd use some #8 hardware cloth, or screen, if you can't get the hardware cloth, and cover all but a couple of inches of the entrance. Then cover the hole on the inner cover (staple it around both these places). Put some over your upper entrance and then prop open the outer cover. This needs to be beeproof except for the two inches of the bottom entrance. This should discourage the robbers. If they continue, I'd close the whole entrance off for most of the morning and see if that stops them. Then open the two inches back up.