I was wondering how entrance feeders worked? Do the bees have to turn upside down to suck the sugar water out from the holes.
Yes. But Boardman feeders have bigger issues than that.
http://robo.bushkillfarms.com/beekeeping/feeder-compare/
I stopped using them in place of top feeders. The Boardman feeders triggered robbing every time I used them.
The way to use a boardman feeder is to take the feeder and give it to someone you don't like. Take the jar and put it over the inner cover hole. :) Then put a box around it and a lid on it.
Yes, they are upside down. But bees are upside down half the time anyway.