This 30 second video was shot by members of the National Poultry Technology Center - Auburn University.  This video clearly shows why having an energy efficient enclosed light fixture is so important in reducing dirt buildup on light fixtures.  Retrolite's NEW 15 watt R30 Dimmable CFL has been designed to place more even light on the floor and to allow for easier cleaning.  Over time bare Spirals appear dimmer, they are actually just dirty and there is no easy way to clean the CFL Spirals.  Just wipe the R30's off with a damp cloth/wipe.  This R30 model has a High Power Factor ballast, which qualifies for utility incentive rebate programs.