Contact them here, and ask about testing supplies, shipping, etc:
https://www.vetdna.com/application/forms/aviansubmittalform.pdf
For information in your state about getting a necropsy, here are the state labs listed:
https://www.metzerfarms.com/poultry-labs.html
Good advice on giving the E orally. B complex crushes a dissolves in food or a spoonful of water, but giving 1/3-1/2 tablet orally is fasted and most accurate. Things I have used to hide medicines are peanut butter, liverwurst, cream cheese, and scrambled egg. With her wry neck and curled toe...