My barn has "dutch" type doors for the goats. The upper panel swings up and is fiberglass to allow light in, while the lower section has a rubber flap ( made from a truck-bed mat ) that the goats quickly learn to use. The flap doors really help to control drafts in the winter and can be swung open for full summer ventilation. A plywood panel is inserted over the flap if the door is meant to be "closed".
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