They're pretty well ventilated. There are vent windows that are covered with hardware cloth from the inside, but open up to allow for more circulation and could be left closed for cold weather. There are vents on all the coops. It depends on the color of the metal too. You wouldn't want to use a dark color metal, but white is best. I never thought about the loud noise from the rain on the tin roof. I've always enjoyed the sound of rain on a tin roof myself. Maybe next time it rains, I'll go investigate to see if it's noisy.
Your coop models are beautiful and obviously very well designed with windows and ventilation. Just goes to show only people who have chickens themselves should be the mfr of good coops!! I love open wired runs for those very humid days we get in summers. It would be nice to know what it sounds like raining on a tin roof to the chickens inside the coop. Someone said they insulated their tin roof to absorb the loud sound of the rain hitting the metal roofs -- plus they said it didn't hurt to insulate under the metal roofs from the heat since metal of any color seems to retain summer heat. I just thought to ask someone who actually mfr'd coops w/tin roofs what feedback they get if any from customers. Because of the feedback I got re: metal roofs I never ordered a coop with metal tops. I guess plywood under the metal roofs would muffle the pounding rainstorms but it would add to the coop weight -- but then, probably no more than a shingled roof weight? Thx for planning to check on the rain sounds .