Need Run help.

What has everyone had the most success with using for a flooring in their run? Our girls have been free ranging for 4 years but have completely DESTROYED our beautiful yard and have now moved onto the neighbors, which they said is okay but they’re also feeding them TONS of food.

Our 15 hens completely destroyed their grassy run in the first day and now it’s all soil/ very wet. So I’m looking to lay down SOME kind of material, sand? Gravel? Something?!

Also what are your favorite accessories in the run that just make your birds happier?