On a plate, or a small tray with a wire rack, pat the chicken completely dry using paper towels.
Season the chicken generously with kosher salt and black pepper on both sides. Leave at least 15 minutes, or preferably in the refrigerator uncovered overnight.
Heat your oven to 450F.
In a dutch oven or other large pot, heat the oil over medium-high heat. In as many batches as necessary brown the chicken legs on both sides, aiming for as crispy a skin as possible. About 5 minutes per side. Remove the legs from the heat and return them to the plate or wire rack. Set aside.
Turn the heat down to medium-low. Add the sage and fry until crispy and dark green.
Next, add the onion, carrots, turnip, chard, and thyme. Season the vegetables with salt and sweat them out until translucent and tender, about 10-15 minutes.
Return the chicken to the dutch oven, skin side up. Add the wine and bay leaves. The liquid should come about ⅔ of the way up the chicken legs, leaving the skin side open to the air. If the wine covers the tops a little bit that’s ok.
Bring the braise to a simmer and then carefully transfer to the oven.
Cook for about 5 minutes, then reduce the heat to 350F and cook for another 30-45 minutes, until the chicken is just done and tender. You should be able to slide a paring knife through it with no resistance.
Remove the dish from the oven and return the chicken to the plate/rack. Remove the bay leaves and discard. Bring the braising liquid to a boil and reduce by about half, until thick and saucy. Depending on how much liquid there is this should take between 7-15 minutes.
Transfer the braising sauce to a serving dish and lay the chicken over it. Top with squeezes of the lemon wedges and serve.