ENVIRONMENT

Queens do take breaks from laying for a lot of reasons.  One is if there's not enough nurse bees to take care of them which shouldn't be the case since you have recently had plenty of brood. 

Another is related to being honey bound.  I learned something that I considered fascinating from a youtube from Norfolk (?) Honey company in England.  When a flow is on, the bees do not pass the honey from bee to bee to bee the way they normally do.  They throw it quickly and temporarily into the bottom brood box until they have time to move it up.  I wonder if they do it at night.  I suspect virtually all house bees are called to take in nectar during a flow, therefore little to no brood raising.

I decided to do some research and found this in an article from Bee Culture

https://www.beeculture.com/time-to-expect-the-unexpected/

This is an excerpt...

Back in 2004, Austrian researchers found that in times of nutritional stress the queen does not necessarily stop laying eggs or even reduce her egg laying, but she does reduce her walking activity within the hive (Schmickl & Crailsheim, 2004). The colony response that does appear to be consistent with lack of adequate food availability is that worker bees will cannibalize eggs and larvae to conserve nutrients (Webster et al., 1987). Eggs and middle-aged larvae are the most likely to be cannibalized. This causes the colony’s larvae demographics to change dramatically within days resulting in a rapid decrease in the older larvae population. During nutritional stress events such as those that occur during a prolonged drought, cells containing the oldest larvae are capped earlier for pupation, while the eggs and younger larvae are cannibalized (Schmickl & Crailsheim, 2001). Researchers found that the less pollen stored by the hive during larvae’s development, the earlier the larvae are capped. This is a logical decision by the bees since the oldest uncapped brood represents the greatest investment in brood care resources. Prior to capping, older larvae also have the greatest need for pollen, so by capping their cells early, the colony is able to compensate for a food supply shortage by reducing the young with the greatest demand. This leads to a quick reduction of older unsealed brood in response to a shortage of available protein. If a period of dearth extends long enough, all the capped brood will hatch and there will be no brood left in the hive due to the egg cannibalization efforts of the nurse bees. This explains why my broodless colony had a queen that looked perfectly normal and she was not shrunken and small from a lack of egg production like a virgin queen who has yet to lay eggs.

Dave, do you know if you have a queen in each hive?  I'd be happy to come take a look with you if you would like... Contact me directly. Not through this forum...