Every serious chicken owner should consider ornamental grasses. There are two basic families: Poaceae, the cereals, and Cyperaceae, the papyrus.
The most common Cyperaceae used as ornamental lawn substitute are many species of Carex, that have typically tougher leaves than the cereals, much less appetizing. Zero maintenance if they have some water. My chicken ignore spots of big Carex pendula, dig paths under the 90cm high grasses and enjoy greatly the cover that it provides. their only secret is not prune Carex, never unless they dry naturally, They aren't cereals. One pruning a year maybe, two maximum. Just let them alone.
Some Carex have the most strange colors and will look exactly like dry grasses. If your chicken eat everythig green, you may want to try the strange rose bronze Carex, (or a silver spear grass).
About Poaceae, any big grasses like Miscanthus will typically be safe with chicken, but those need much more space to grow. Miscanthus zebrinus is pretty. Just plant several and plant them dense. Will start as a whole gren leaves but soon, surprise.
Is --very-- important to avoid ornamental grasses that are known as invasive in your area. Cortaderia is not advised. The japanese Miscanthus is beautiful, but if they seed in your area be responsible and forget it.
In USA a very good replacement is the native Panicum virgatum, super-vertical even for a grass, nice colors in summer and striking changes of colors in fall. A very good one also for interest on winter with snow, Its main problem is that is a warm season grass, and will sleep until spring. It starts growing very late in the year and can be as tall as a man, but in april there will not be any grass except the dry one from the previous year. Cut it at a few cm from the soil, just before it wakes up. If the chicken eat the new leaves just provide some cover until it grows far from its reach
In any case, as long as the roots are protected and the grass is vigorous, every species will work. A reasonable amount of chicken will feed on it but the grass will jusr regrow again. With a few stones placed strategically, the chicken will absolutely love to take cover, scratch for grains, rest and nest under it.