To make sure it's done, test to make sure toothpick comes out clean from thick part of the cake. (localappetitenyc.com)
Roast bird, breast side up, in a large, lightly oiled roasting pan on the lower portion of oven at 350 degrees F. for first 30 minutes then reduce heat to 325 degrees F. Continue to roast, basting often, until thermometer inserted into thickest part of thigh reads 180 degrees F. about 2 to 2 1/2 hours. (foodnetwork.ca)
Cook chickens until thermometer inserted in thickest part of thigh registers 170 degrees, about 50 minutes. (dineanddish.net)