I used plastic boxes first. Very easy to clean, mine hung on the wall in the coop. The girls used them fine but they didn't allow enough ventilation in my climate. We switched to a single wood frame, no bottom, with lattice dividers they can actually make a nest in. Much better.
FWIW I treat my coop every Spring and Fall with permethrine to prevent mites. I also whitewash the interior which helps a ton and is non toxic to your birds and other animals.
FWIW I treat my coop every Spring and Fall with permethrine to prevent mites. I also whitewash the interior which helps a ton and is non toxic to your birds and other animals.