TrailManor refrigerator concern

We have decided that the more the refrigerator is filled, the less efficient it is.  Things on the door will be barely cool, not ice cold like you like your sodas.  This is probably because the air circulation efficiency is lowered.  Being that the cold comes from the top of the refrigerator, food packages block prevent the colder air currents from reaching the bottom and door area.  We bought a small fan (about three inches tall and about three inches around) from Camping world (about $12.00?). Its color is pale blue aand it  runs on two d cell batteries.  The batteries are supposedly good for 600? hours. The fan is so small that you can barely feel it working.  We placed it on the bottom shelf.  Whenever we are not using the refrigerator (between campouts) we pull the batteries.  The batteries are still good after a six months use.