listen very closely to the hive-in the evening and knock on it-gently of course
if it goes BUZZZzzzz----......
it means that you either have a queen, they have a queen cell or in worst case a laying worker
now, if the sound goes BUUUZZTZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ and so on snd so on, they are most probably queenless.
now i'm not sure how well you can listen to a LR hive but with my hives this is a pretty good method. and it really works, also, if you have time, look at what they're bringing in, if there's no pollen, it might be a sign of a queenless hive