My coop has plywood walls on all four sides and small vents at the top. My four chickens (Orpington, Australorp, RIR, and Polish) are all about 8 months old. Recently it's been about 45-65 degrees during the day, and about 35-45 degrees at night. Do we need any extra heat? I still have a heat lamp left over from when they were chicks ... do we need to use that or not, because I don't want to waste any extra electricity ... ? I live in the Portland area in Oregon.