So here, I think, is a new one. I have both hens and rabbits free-ranging in my back yard. Tonight, when I went to collect my eggs from the chicken coop, I found one of my female rabbits sitting in the nesting box. I reached underneath her, and sure enough, she was sitting on 4 eggs, keeping...
I think many/most chicken tractors have a coop incorporated, so I don't think you would need a second coop:
https://www.backyardchickens.com/chicken-coop-tractor.html