My ventilation is at the top underneath the roof line all the way around. I kept the side down from the roof about an inch. I clean the tractor every day so there is no build up of odors ammonia or otherwise. Later I will add a window that pops down with screen in it for the sides for this summer, and I am moving them under the trees in late spring. It is always 15 degrees cooler there and it is on the creek. Coop # 1 has been up and running for a week now with no smell. I have lots of shavings in there so it is super easy to keep clean. Just take out the dirty and fluff up the rest.
I just finished my 5th one tonight. I started two today and completed them. I hurt all over. I got my first egg laid in coop # 2 so that is a good sign, and she laid it in the nest box like a good girl. It took her a week to lay an egg last time I moved her. This time there was no pause so that is cool.
I am very happy with the last two. I have the door on the back side and it opens out revealing the entire interior for easy access and cleaning. I am going to changes the hinges on the others so they open out instead of down. Much easier to get in and clean without leaning over the door.
Lanae