Where can i buy a protective collar for my dog for hunting?

i have a german shep lab mix and she is my hunting dog she kills raccoons and opossums and i want her neck to be safe what is a website i can buy one for cheap that will fit her she is about the size of a lab but more thick cause she is built in muscle from the way i train her she listens and is up to date on all her shots and knows what she is doing she has done this for years with no issues like just the other day a possum was on my back deck i could not shoot it cause of the chance of hitting something or the bullet bouncing off and hitting someone so i sent her out she did the job fast and clean but had a bite on her neck took her to the vet no issues but i want her protected