Hello, I'm trying to decide the placement of a medium sized coop. I don't have much grass on our acre of property, most of it is graveled, and about 1/4 will be turned into a garden. I'm wondering - does a permanent coop have to have grass? Where I plan to build, it would be situated on gravel. I hope to let the chickens out most days to forage and wander around the yard, but am unsure if this will happen daily (for example, when I'm away for the weekend). If building the run/coop on gravel is ok, should I put anything down? Like straw? Or sand? Or is the gravel sufficient? Thanks in advance!