I've noticed on the colder mornings lately there are more dead bees and pupae on the landing than usual?
Not only there, but dead or slightly moving bees are clogging the reduced entrances.
Could that be because it's too cold for the bees to completely drag them off the landing?
Just guessing here but maybe in summer there are the same amount of bees dying but the living bees a better able to keep the landing cleaned off.

Should I clear the entrances or let them do it?

We have a cold morning here and its seems strange to not see see them out like when its warm weather.
Hope they are ready for winter.