Bake at 425° for 1.5 hours.
To check for doneness - pierce the thickest piece of your largest hen with a knife. If its fluids run clear - you're good to go. Or, if your hens register 165° F with a thermometer.
Also, use your carrots as your best [doneness] indicator for your veggies. If a knife slides easily thru them - everything else is fully baked. Including your potatoes.