I found new, in the box, exterior wall vents (24"x30") for $5 at Habitat for Humanity. Bought one - should I buy another one? These are made from molded resin - has slats on both sides with screen inside - doesn't look like much light, snow or rain will get in but will vent the coop. I hope to build a coop big enough for 5 chickens - plus a run.