I’ve never had purpose-made bait hives. I just use old brood boxes that aren’t really good enough for bees to over-winter in. I paint them a dark green/grey so I can tell them apart from all the others. Then I use a purpose-made floor that has a 38mm diameter hole in one side as an entrance. I wanted some more bait hives so I could dot a few around the local town with a view to tempting bees in rather than having them find local chimneys or roofs and suchlike, so I went a bit mad making more.
Having made them it occurred to me that I could 3d print an entrance piece that would allow me to close off the hive to move it, so I fired up FreeCAD and this is what I came up with.
By the time I actually settled on a final design I’d added a bar down the middle of the entrance hole to discourage birds from using it as a nest and (unfortunately not visible in this photo) a small tab that allows the slider to be fixed in the closed position.
