Re: Queen Excluder or not
Keeping queens confined to the brood nest with an excluder is invaluable in controlling shb in your extracting facility. I also think (but dont have actual proof of this) that it keeps any issues with chemical residues in older brood combs from tainting any of your honey supers. A top entrance of some sort is probably a good idea if for no other reason than ventilation.
"People will generally accept facts as truth only if the facts agree with what they already believe."- Andy Rooney