I keep robber screens on my hives year round upon the advice on a previous post when I was trying to protect my hens and myself when I mow the lawn from the attacks of my honey bee girls. The robber screens do, in fact, keep them calmer. They never bother the hens anymore and they seldom butt me now when I'm mowing or trimming. I did my first spring inspection last Thursday and have a hive that is ripe to swarm, with numerous queen cells, lots of honey and pollen. I've checkerboarded, but at this late date, it's not going to stop them. I want to split it, but haven't had time. I have a new hive set up for them to use for either a captured swarm or if they hang in there until Tuesday for me to make the split. But my question remains. . .is it possible the robber screen is discouraging the queens egress?