I have to wonder if this is a situation where someone ordered more bantams than they needed for shipping purposes and is selling off the extras or if they have bantams they're allowing to hatch eggs and are selling off the offspring? Knowing this would make a big difference because if they are selling their birds' offspring, these would most likely all be mixes while a hatchery order would be hatchery quality examples of breeds (which occasionally have defects like wrong comb type or wrong leg color).