Place the ham in the slow cooker, cut side down if it will fit that way. In a small bowl mix together the zest, juice, honey, maple syrup, dijon, and allspice.
Pour half of this mixture over the ham, and top with thyme sprigs and pineapple slices.
Cover, cooking on high for 3-4 hours, or on low for 6-8 hours, or until heated through with an internal temperature of at least 145℉.
Place the remaining glaze into a small saucepan and heat on the stove over medium heat until mixture becomes thicker and more concentrated, about 5 minutes. Remove from heat.
Remove the ham to a wire baking rack lined sheet pan and baste the ham with the glaze just before serving. For extra crispy and sticky glaze, turn ham onto it’s side, place ham under the broiler of your oven on low, watching closely until the glaze starts to bubble and brown on the edges of the ham.
Serve ham warm, or at room temperature, with any remaining glaze.