My backyard (or backwoods) flock is made up of as many different breeds (white rock, ameracauna, speckled sussex, buff orpington, barred rock, black australorp, black copper and birchen marans, and one mystery black hen with a red comb and white ear lobes) as I could find. The coop and pen that I have for them is isolated out in the woods on property that's going to be developed into an organic subsistence farm. The main challenge I faced when designing the chicken pen was that I live 30 mins away, and can't make it there every day. The problems that arise therefore are exposure to predators, coop access, and food and water storage. The chicken coop is located inside of a wire fence which helps keep out foxes, coyotes, and such. Also, plastic flaps covering the chicken door into the coop allows them access to a place to hide from hawks and owls. But the main security feature I settled on to give myself complete peace of mind while miles away from the flock is having a guard puppy on site.
Also, as you can see in the background, I threw together a large feeder that can hold up to a bag and a half of feed, and bought a waterer from the pet store that holds two and a half gallons. With the dog trained to protect the birds and food and water to last a week, I now only have to commute at least every other day to let them free range and to collect eggs!