Dead bees at the hive entrance

Hi all

Ive just taken delivery of 3 hives. I have had them a week today and just noticed that on 2 hives there are 2-3 clusters of 20 or so bees on the ground outside the hive clinging together for warmth. Are there winter bees being turfed out to perish or should I be concerned. The more advanced hive has more bees on the floor than the lesser advanced, the beas appear in perfect health in appearance.

Any ideas?

thanks Mark.