I recently installed a Nutone GF1200N Gable-Mounted Fan with a Wind Blown Automatic Louver. The Louver is plastic/vinyl. The shutters blow open by the force of the wind created by the fan. They close when the fan is off. They do not close super tight. My question is. Can I secure a screen in the small space between the Louver and the Fan to keep out bugs and birds? If so, is there a limit on the measurement of the screening? I'm guessing anything under a quarter inch would just get blown out. Maybe a bigger screen would be sufficient to just keep out birds,bats and squirrels. Thanks for any feedback.