Any ideas on how to ventilate a windowless bathroom in a 150 unit coop building, I own my unit?

There is vent that draws air out and up to the roof located in the shower, but that is it. The bathroom gets VERY steamy even if you take a warm shower and leave the door open, which is fine if one lives alone. I have thought of adding a transom above the door to increase airflow and allow steam to escape. I have 8 ft ceilings. Any ideas? Bathroom measures approx 7 x 5.