I had the same goals as you. A well fortified tractor makes keeping a flock very easy on us and provides a great quality of life for the chickens.
I don't know if what I did is more than you want to do, but it might have some ideas you can use. We've been using it since August, and knock on wood, haven't lost any of our 12 hens and their rooster. Here's a link if you'd like to check out the photos.
https://www.backyardchickens.com/th...or-thanks-to-you-guys-and-your-ideas.1213066/
I don't know if what I did is more than you want to do, but it might have some ideas you can use. We've been using it since August, and knock on wood, haven't lost any of our 12 hens and their rooster. Here's a link if you'd like to check out the photos.
https://www.backyardchickens.com/th...or-thanks-to-you-guys-and-your-ideas.1213066/