I don't know the laws in Missouri, so first check with your DNR. Then, once you know if you can use them, there will be licensed dealers. Contact them and tell them your situation. Stock no more than 4 per acre in the beginning. Since you have big flatheads, you need to stock the biggest grass carp available. Several hatcheries south of you in Arkansas have them. Buy them later winter, or early spring. You may be able to buy fish several pounds apiece.

Teach a man to grow fish...
He can teach to catch fish...