from your description, i'd say these are carniolan bees
about swarming...i'd say this has changed a bit. throu decades of exporting bees-that is rush feeding-forcing them to swarm, bees have adopted this way, that's why they started the "swarming with no reason" thing. this is slowly changing, but i don't have experience with it jet, since it was my first year.
this year is like you all know, extreme, hazel tree has already blossomed so yeah, they're bringing in loads of pollen (this should happen somewhere in the end of february, i'm not sure) they're rearing lots of brood, i was at the local beekeeping society meeting, some say they have up to 3 frames of brood, and this oughta be a problem if cold kicks in.
carniolans overwinter with pollen, that's why they have a faster spring build-up than other species. the bottom line is, bees can adept to some degree, especially about the pollen thing you're worried about.