you probably had a good brood break. i know i did. best thing you can do is encourage good build up. i am not opposed to treating when you need to, but if it can be avoided it's best for your bees and your pocketbook :-).
encouraging buildup is part of the reason i don't buy the rotation of supers bit. the less you disturb, the better. there are time when rotation needs to be considered, but most of the time the bees will do a fine job without interference. my admittedly limited experience and observations have led me to conclude that those hives that require the most manipulation, are the least likely to survive and thrive anyway.