Preheat oven to 425 degrees F.
Whisk all the marinade ingredients together (beer through chipotle pepper). Pour over the chicken legs and marinate in the refrigerator for at least 4 hours, turning to coat halfway through marinating time.
Place chicken legs on a parchment paper lined baking sheet. Bake for 20 minutes.
Meanwhile, pour the marinade in a sauce pan and boil. Reduce heat to simmer and allow to cook for at least 20 minutes, until marinade thickens and is reduced to about 1/2 cup.
Remove the chicken legs, flip over, brush with the reduced marinade and bake for 10 minutes.
Remove the chicken legs again, flip over again, brush with the reduced marinade again and bake for an additional 10 minutes. So the chicken legs will bake for a total of 40 minutes.
Chicken needs to be cooked to at least 165 degrees F to be safe to eat.