All you have to do is remove the top cover and the inner cover if you have them you will know it. Hive crowded and in full sun. Just don't put 10 frames of honey in a hive with 2 frames of bees for protection. They will not bother foundation so fill the hive with foundation, and drawn combs that the bees can cover.
This is good advice. If you have SHB you will know as soon as you lift the cover. Don't give the bees any more space to defend than you have bees to protect.
Steve