We had planned on purchasing polycarb for the coop's roof but it was $27 a sheet!! Then we saw corrugated metal is only $14.40 a sheet so we bought that. Besides being cheaper, the metal can be sold for scrap if it's no longer needed where we would have to pay to take polycarb to the dump. We may still get some polycarb for the run when we feel more flush. For now the top of the run will be chicken wire. Also my honey thinks the metal will be easier to install than the polycarb.