So you stuffed the cotton ball in the hole after they moved into the box? This is what I'm reading into it. If so, and they moved in on their own, you were very fortunate it went down like this. Usually there is a tussle.
you probably wont get that lucky again!good job though.they must not have had enough room to set up shop in the bricks.did you use old brood comb in the bait hive or just lemon grass oil?bailey