1. To Make Sauce: Melt butter in a small saucepan over medium heat. Blend in salt, pepper and flour, then add milk and cheese. Simmer, stirring constantly, until thickened. Remove from heat, cover and set aside.
2. To Make Garlic Butter: Melt butter in a small saucepan over medium heat. Blend in garlic, rosemary and salt. Cook, stirring constantly, until garlic is tender but not browned. Remove from heat, cover and set aside.
3. To Make Dough: In a medium bowl, dissolve yeast in warm water. Add oil, sugar, salt and flour. Mix together and knead mixture until a smooth ball forms.
4. Preheat oven to 400 degrees F (200 degrees C). Season roasted chicken with rosemary, thyme, poultry seasoning, garlic powder and salt. Chop or shred and reserve.
5. To Assemble Pizza: Spread dough out on prepared pizza stone. Top with cooled garlic butter, covering entire crust. Next spread with Alfredo Sauce (if necessary, warm to spreading consistency), leaving crust edges. Top with chicken, turning to coat with sauce.
6. Bake in preheated oven for 20 minutes, or until bottom crust is lightly browned. Remove from oven and let set for 2 to 3 minutes before cutting.