Could you get closer pictures please? I am leaning towards hatchery quality White Orpingtons, with at least one rooster. But closer pictures are needed for confirmation.
They do look like roos, I think I can see those sickle and saddle feathers on them though with all the white it's really hard to see! How old are they? Look like White Plymouth Rocks to me, though the legs are pretty pale. Maybe White Orpington? Though they're not quite bulky enough for that.