Just beautiful! I love the way the walls and roosts feel very natural and I bet the chickens do, too! I agree that the chickens may not need the supplemental heat, and I would put the ventilation higher up, since if you put it lower, you might get cold drafts on their toes and in the nest boxes. And if you know which direction the harshest winds in your areas come from, you can vent on the opposite side.
You are so lucky to be building with your father...mine wouldn't show me how to do anything because I was a girl. I've relied on Building Chicken Coops for Dummies to teach myself to choose and use tools so I can work on my chicken apparatus.
Are you planning to free range them, too?