Welcome. Glad you decided to join our flock. My wife & I were both raised about an hour NE of Dallas (Blue Ridge & Greenville). The dimensions of your coop & run are fine. As for breeds, I have raised dozens of breeds over the past 50 years & I am convinced that the best breed to meet your criteria is the black australorp. I have raised them for years, including in your area, & they are extremely hardy. I raised them in northern Kansas where the temperature dropped to 30F below zero one winter, & in CA where summer temperatures frequently reached 117-118F (123F once), & in both climate extremes they came through like troopers. They are also very calm & gentle birds. My children, & now my granddaughter, made lap pets of them. And they are the best layers of the standard, brown egg laying breeds. Until it was broken by a caged White leghorn (which are high strung & flighty) in 1979, a black australorp held the world laying record with 364 eggs in 365 days (still the brown egg laying record), & while my BAs have never had that kind of production (& likely never will), I have still had a few of them lay over 300 eggs in a year. Whatever breeds you decide to get, good luck with your flock.
