Thanks for your advice. I'm learning here!I asked him about the ventilation actually, that was my first thought. He said they use a similar coop and that because it is not manufactured wood, it still retains moisture and that as it drys, it will contract and give lots of gaps between the wooding on the side(he compared it to a barn) and that will allow plenty of ventilation and light. I asked if it needed an additional window and he said definitely not.
I'm open to opinions. We want the best for our chickies!
I commend you for doing your research and learning about chickens!
I have to disagree with the coop builder's opinion. I don't think he is truly aware of just how much ventilation chickens need. I have a breeding coop that is basically the same size and it has a built on 8'x4' run that is almost 5' high. I wouldn't put more than 4-5 full-grown bantam (small-breed) birds in there - and only that many because they have free 24x7 access to the run so they can get away from each other. My 4'x4' coop is made of wood and it has three 3" round vents on one side and a 12" x 12" window and two 3" round vents on the other side. It also stands up off the ground and the 12" x 18" trap door in the floor is always open, no matter how cold it gets to allow the air to pull the moisture up and out the top vents.
I do lower the flap on the window on the coldest nights, but always leave it open by a few inches. If it is above freezing, the window stays all the way open.
I say go for a bigger coop with tons and tons of ventilation. You might be happy with that small coop for the first 12 weeks or so, but then you'll wish you had a much bigger one when your birds are getting large and starting to fight with each other in a small space.