Split each biscuit on a separate plate; set aside.
Heat a drizzle of olive oil in a skillet over medium-high heat. Add the chicken sausage, and stir with a wooden spoon to crumble. Cook until lightly browned, about 5-6 minutes. Set aside.
In a small bowl, whisk together the flour through sage. Slowly add milk, and whisk to combine.
Heat a small saucepan over medium heat. Add in the flour-milk mixture, and bring to a simmer, whisking constantly. Reduce heat to low and simmer until thickened, 1-2 minutes, whisking constantly.
Stir the cooked sausage into the warm gravy, and spoon over the split biscuits. Finish with an extra grinding of black pepper.
Homemade Chicken Breakfast Sausage: In a bowl, combine all ingredients; mix well.