bee death on external feeder
Not sure if this is the right forum to post this question, but I am a new beek since August with one top bar hive. I'm feeding the bees syrup constantly to get them to build up comb and stores. They go through about 32 oz a day. Aside from the sugar, I am also using a few drops of essential oils in the water. Either anise oil, wintergreen or sprearmint. Most days they take it just fine. About once every 2 weeks, I come home to find an empty feeder and a pile of dead bees near the feeder. This is a boardman type feeder that is set away from the hive on a platform about 8 ft from the hive. I'm not home during the day to see what goes on. But I can't figure out the bee death. Any suggestions?
I've also gotten an in-hive feeder, but I find that I can't leave that in for more than 2 days at a time or the hive beetles begin to lay larvae in spots where the bees can't clean them out.