Place chicken carcass into a large pot and cover with water. Bring to a boil over high heat, then reduce heat to medium low and simmer for 5 minutes. Drain, rinse carcass under running water, and return to the pot.
Add galangal, lemongrass, lime leaves, shallot, garlic, and chiles. Pour in 10 cups water. Bring to a boil over high heat, then reduce heat to medium low and simmer uncovered for 1 1/2 hours, skimming the foam and fat often.
Strain stock through cheesecloth before using.
Thai Chicken Stock · Dinner Match Lab | Dinner Match Lab