Thread 'Plants In The Chicken Run! A Mini Forest For Chickens!' https://www.backyardchickens.com/threads/plants-in-the-chicken-run-a-mini-forest-for-chickens.1540569/
If you do pinterest - search "plants in chicken runs". Google, too. Lots of hardy shrubs, plants, fruit trees that can go in the run(s) & also on the outside, based on your zone/state.
Seeds & young plants need to be protected while starting & until established (maybe roots, forever - but our...