I was going to get two chickens, but somehow wound up with four chicks.... the coop is going to be cozy and will probably need to be expanded. In addition I'd like to build a fairly large, preferably portable covered run. Given that we live in the desert and the ground on which the run will be sited is very hard caliche with no forage to speak of, what would be a good size for four standard hens? What's a good design for a covered run that would keep them reasonably safe from the ubiquitous hawks? What can I put in a run to help keep them entertained given the fact that there won't be grass to pick through?