What's the matter...Chicken?

We have decided good or ill to pursue raising chickens. We had a brief experience with chickens when we rented from a farmer and his coop was close to our dwelling. We picked eggs, fed and watered them on occasion and helped butcher. So armored with that brief experience and a liberal application of research we want to get some chicks for meat and eggs. We have settled on "Black Austrolorps" for our egg layers as they are a gentle friendly breed and are good for eating also. The "Meat" birds are a hybrid from http://www.mcmurrayhatchery.com/index.html that grow quite fast without suffering (Hopefully) the disabilities of commercially grown chickens. They are called "Cornish Roasters" and reach 4 to 6 pounds on 8 to 10 weeks.

We debated for awhile how to keep them, penned or free range. Each has it's drawbacks, messy birds and risk of disease for penned birds and predator losses for free range. So far we are leaning heavily towards free range as I believe I can build a predator resistant coop for night time. Having free ranging birds would also hopefully reduce the bug population around here. Our landlords have horses and it doesn't seem to matter how far away they are, the flies are ever present. Last year there were so many grass hoppers eating our garden, we could stand to have a little grasshopper feast as well. As for the penn/coop itself, I am thinking of building a geodesic dome and covering 3/4 with chicken wire and the rest with plywood. That way if we are going to be gone or there is bad weather, the chickens can be penned for a short time. The plans for the dome come from this site: http://www.geo-dome.co.uk/ If you end up using his calculator tools remember he's British and the tools are in Millimeters. I will be posting pictures of the coop once built and chicks once we get them.