Do the queens continue to lay through the winter?
Yes they will keep several frames within the cluster with Eisenhower dollar sized brood nests throughout the winter to mitigate older summer bees dying off and some loss due to cleansing flights during colder weather who might not return.
Oh thre are queens the nicest looking big fat black queen I have ever seen a big fat orange queen very nice looking just wandering around the frames
What is the genus of the bees? Some subspecies, like Russian and Carniolan, occasionally take hiatus's from laying eggs as a form of Varroa mite control. Try placing a drop of lemon grass oil on the center brood frame, that will sometimes work to prompt a queen in hiatus to begin laying. The best method, when possible, is to drop in a frame of newly laid eggs from another hive.