Certainly swap their positions over. I'd suggest separating them a little farther apart - to around 12-18" if possible. If this is out of the question, then rotate one box 180 degrees so that their entrances are oriented in opposite directions, (say) one facing East, the other facing West.
If the foragers always return from the same direction, try to ensure that the entrances are 'square on' to that direction, as some types of bee are prone to drifting, and will enter the first entrance they come to on their return - especially if the hives are lined-up in a row, where the end hives frequently amass more bees, at the expense of the others.
Separation by a fair distance is the best solution, but different orientations of entrances helps - as does having different coloured entrances.
LJ