Here are some recommendations from the austin poultry list for Avian Vets so you can take your chickens in for help. Thanks to Carla for this.
My local vet in San Marcos is not an avian vet, but he treats chickens and other farm animals (and lamas, and exotics) in addition to cats and dogs. I really like him, but he does admit he is not a chicken expert. He is also very compassionate.
Mark Williams - 512-396-1996
The best place for necropsies is TVMDL_- Texas Veterinary Medical Diagnostic Lab in Gonzales or College Station. Gonzales deals strictly in chickens and the cost is only $15. You can watch if you want, and Dr. Linares will personally discuss the results with you. 830-672-2834 My vet does bird necropsies for $20.
I found some Austin recommendations for avian vets on the web and two were from Westgate Pet & Bird Hospital. (512) 892-4463 There are also a couple in San Antonio. Thomas E. Vice (210) 824-7481 and Dr. Kirby (210) 821-5544
Please let us know how your experience is with any of these folks in the comments.
BTW. These pictures are of my girls who were recently attacked by a very friendly puppy.
Update: Paula Tarvey added: This very will also be far for you but they are fabulous. Sunset Canyon Vet Clinic almost to Dripping Springs. 512-894-0266.