I'll have to try the Atwoods in Owasso, since the TSC in Skiatook apparently doesn't carry it. At least not that I've seen.
You guys have probably already seen this information dozens of times (Rinda probably has the numbers memorized), but here it is one more time in case you need it...
The OK Dept of Agriculture offers free necropsy services on poultry. What they require is a non-frozen, fresh carcass (keep it refrigerated after death if you can). You can take the carcass to them, or if you live in a rural area or far enough away, you can call them, and they arrange shipping, all free of charge.
You can contact Dr. Herrin at the DoA, 405-522-6142, or Sherri, the woman who runs their dept, 405-522-6139. I just talked to Dr. Herrin and he's REALLY nice, very personable and easy to talk to. They make the arrangements with you and get it taken care of.