Preheat your oven to 425˚F.
Using a sharp knife or kitchen shears, butterfly the chicken by cutting along either side of the spine and removing it. (Alternatively, ask the Calgary Co-op butcher to do it for you.)
Open up the chicken and place it cut-side down on a parchment-lined rimmed baking sheet.
Spread the vegetables (reserving the rosemary) out around the chicken or turkey and drizzle everything with oil.
Rub the oil all over the surface of the chicken, and toss the veggies with your hands to coat.
Sprinkle everything with salt, and tuck the sprigs of rosemary in to the vegetables or under the chicken.
Roast for 45-50 minutes, stirring the veggies once or twice, until the juices run clear and the internal temperature reaches 165˚F.