If it is sweating you have too much moisture in air inside. Not enough ventilation would be my guess. If plywood or OSB stops sweating be advised that you may have mold by end of winter, because dampness is still there. Is floor dirt or wood? Best place for full-time ventilation is at the top of the walls or the top of the gable ends. A ventilated cupola would work well as would a turbine nvent if coop is big enough.