plants that chickens can eat but not kill

[chicken vs duck]

Just need some ground covers within the pen

 

[Folly's place]

Shrubs are good, but your pen will have to be huge for most low growing plants to survive. Maybe mint? Only the totally inedible weeds make it in my run. I've got shrubs around it for shade and shelter. Mary

 

[centrarchid]

Plants they have limited access to or where birds can move about looking for other eats as well like enabled with free-range foraging. With confined birds think exclosures not unlike use to protect tomatoes. Birds can eat parts they can reach but if sized right much of plant will be out of reach.

 

[chicken vs duck]

The pen is 20×20 so I might try shrubs aswell as centrarchid's idea

 

[Folly's place]

Avoid the really toxic plants, like Japanese Yew, rhododendrons, etc. I like plants with edible berries myself. mary