Preheat oven to 400 degrees F.
Cut head of garlic, about 1/4-inch, to expose tops of garlic cloves. Place garlic head, cut side up, in a sheet of foil. Drizzle with olive oil; season with salt and pepper, to taste. Fold up all 4 sides of the foil and cover tightly.
Place into oven and roast until cloves are golden brown and tender, about 35-40 minutes. Let cool before squeezing cloves from skin; reserve and mince 8 garlic cloves.*
Preheat oven to 450 degrees F. Lightly coat a baking sheet or pizza pan with olive oil.
Heat 2 tablespoons olive oil in a large skillet over medium high heat. Season chicken with salt and pepper, to taste. Add chicken to the skillet and cook, flipping once, until cooked through, about 3-4 minutes per side. Let cool before dicing into bite-size pieces.
Heat remaining 1 tablespoon olive oil in the skillet. Stir in spinach until wilted, about 2-3 minutes; season with red pepper flakes, salt and pepper. Set aside.
In a small bowl, whisk together ricotta cheese, thyme, oregano, basil and reserved garlic cloves; season with salt and pepper, to taste.
Working on a surface that has been sprinkled with cornmeal, roll out the pizza into a 12-inch-diameter round. Transfer to prepared baking sheet or pizza pan.
Top with mozzarella, dollops of ricotta mixture, chicken and spinach.
Place into oven and bake for 15-20 minutes, or until the crust is golden brown and the cheeses have melted.