Nice coop and beautiful birds. It looks very roomy.
I have a couple of questions though. Is this the birds' permanent coop or do they go inside another coop at night ? What type of predators do you have in your area ?
A couple of suggestions too.
Since we are getting into winter, a solid wall at the lower end and on at least one side will give them a wind break. It will also help keep water from splashing into the tractor when it rains and prevent the the feed from getting wet.
Chickens don't use swinging roosts like smaller birds. It is also harder for them to get on to. Can you put another 2x4 brace in the middle and another one at the end of the tractor ? You could then attach the roost to it. There would be plenty of room for the birds to walk around the posts and you could then put the feed and waterer where there isn't a roost.