In a large bowl, combine ground chicken, olive oil, salt, pepper, sage, thyme, fennel seeds, paprika, red pepper flakes, and brown sugar.

Slowly add the ice water while mixing the meat with your hands. Mix gently but thoroughly until the spices are evenly distributed and the mixture is slightly sticky.

(Optional) If using casings, soak them according to package instructions.

Fit your sausage stuffer with the appropriate nozzle and slide the casing onto it. Carefully feed the chicken mixture into the stuffer and fill the casing, forming one long coil.

Twist the filled sausage into 4-inch links by pinching and rotating in opposite directions between each link.

Alternatively, form small patties or hand-roll link shapes without casings.

Cook the sausages over medium heat in a skillet with a little oil, about 4–5 minutes per side, until golden brown and fully cooked through (internal temp of 165°F).

Serve hot or cool completely and refrigerate or freeze for later use.