Should I use screened (1/2" or 1/4" hardware cloth) or solid (plywood) bottoms in our nest boxes? I understand the rationale for screened one is to allow poop/dust to fall through and only good bedding to remain in the box. Does it really work or does it only ad limitations on what to use as nest bedding - i.e. can't use small wood shavings or sawdust with screen bottoms? Any other pros/cons of either?