Place chicken in pot on a bed of root vegetables and herbs, such as onions, carrots, celery, garlic, sliced orange and bundle of herbs (bay, cilantro or parsley and oregano). Cover meat with water by an inch or 2 and bring to a boil. Reduce the heat to keep at a low, rolling simmer and poach chicken 40-45 minutes. Remove the meat to shallow dish, cool to handle and then strain liquids.
Broil or char poblanos on stove top to blacken skins evenly. Place poblanos in a bowl and cover with plastic wrap, cool to handle, seed and stem peppers and finely chop them.
Place anchos in small pot and cover with poaching liquid, about 2 cups. Bring to a boil, reduce heat and simmer a few minutes to soften, puree until smooth in processor or blender.