My three have two dog runs on concrete with a big hutch at one end and hay bales and a big log at the other. I give them other toys too from time to time but they mostly eat them in the end!
To get around them not having access to grass I pick grass, dandelion, chickweed, docks, sow thistle, groundsel etc for them twice a day as well as veg scraps from the kitchen and their Burgess Excel. They seem in fine fettle!
