The Henderson's chart is very useful for determining the hardiness, etc of a particular breed. I have to say however, that you should get the breed that tickles your fancy! Also, some breeds that were described here as "sometime flighty", such as the Golden Campine, for me have been the most endearing breed that I have had to date. Sometimes you just have to take the chance on a breed. I would say in Texas that the lighter breeds might be better for heat tolerance.

Here is a link that might be useful: Henderson's Chicken Chart

For plans I look at Murray McMurray Hatchery web site and chicken I'm trying are Buff Orpingtons pure Gold colored chicken can lay all winter. There about 9 weeks old now one real good kinfolks gave me 20 and said take back all males so now I have 12 left 3 males and 9 hens I'm going to set on that number until get grown. Real gental breed of chicken they all come to my new coop door me rub there chest. Out 20 never had sick looking one. I will have to proved coolness for this breed in summer months of july and august there wind be in location has free wind and shade cloth over the coop and run if this don't work I will get smallest air conditioner some people spend 1000's on dog and don't get eggs. I'm 65 and build coop to last rest my life 3/4 treat plywood and 4 inch treated post and good many treated 2x4's box size 4 foot in all directions run off ground 4 foot by 10 foot run flyway 1/2 hardware wire my coop 4 foot off ground so good working level to feed change water and feed. In side 4 foot box is red heat lamp and very small electric heater with thermostat heat plus backup hunter have small propane heater I'll get for electric outages. This coop made so be moved with hay forks on frontend loader are pulled like sled so its now in warm spot will be move to cooler spot next spring. There lift up door at back box so be clean out new shaving be added to floor and eggs when come be picked up.

I have Buff Orpingtons too. Here in NH we have some very hot, humid days and the buffs are definitely stressed even in the shade. I have a fan for days like that. They do really great in -20 degree weather and do lay all winter long here where we have less than 12 hours of light each day in the winter.

We're in Central Texas, zone 8, and have a small flock of Black Australorps (an Orpington off-shoot) and are very happy with them. They are gentle, lay large brown eggs, can handle the heat and the cold, and we haven't had any disease problems with them. We got them as hatchlings from Ideal Poultry.

Have you checked out the Sexlink breed. They did well for us in Florida as well as TN. Fairly early layer, will set only occastionally. Extra large brown eggs year round both places for me. They have a red and a black as well. You can also sex the birds as hatchlings One has a yellow spot on it's head the other sex doesn't.
Mike

I had turkey necks when I lived in Lawton, OK and have to say though they were god awful ugly but they were incredibly good layers. Big too. Would probably be good meat chickens if you'd like that. They were also very healthy and hardy.
I had two in a batch of chicks (they were my bonus chicks) and by the following year I seemed to have dozens and dozens. They were obviously very virile and hardy. They just reproduced like crazy. They were very gentle, almost to the point of being a little stupid. But you had to almost feel sorry for them, they're so darn ugly.