I've recently discovered this source: http://www.beesource.com/point-of-view/jerry-hayes/queen-excluder-or-honey-excluder/ And it's led me to wonder whether I should even use excluders. I have an apiary site, in scrub land Australia, with 6 well established, mostly strong hives. These hives have been neglected, and the comb inside is dark and foul. I don't wish the bees to lay brood in the comb I wish to use to extract honey, but I also don't want to reduce the efficiency of my hives. Under these conditions, should I make the effort in installing queen excluders? If I wish to use queen excluders in the future, should I use hives that have upper entrances instead of lower?