This is more a technique than a recipe, but it's special in our household because my 10 yo son can do this with minimal help. I have no idea why it's called a medieval chicken, but I originally got the recipe from a colleague. We have never used a cut-up, boneless, skinless or unprepared whole chicken, so I don't know how one would adjust the recipe to work with those cuts. You can substitute smaller roasters or cornish game hens, but adjust the cooking time accordingly. To learn to spatchcock the bird, ask the butcher to do this or check on the internet for a video.