Clean and wash the whole chicken in and out. Salt the chicken inside and out and put it aside. Whisk the yogurt in a bowl and add half a cup of water. Add oil, thyme, black pepper, red pepper flakes, salt and crushed garlic and mix completely. Smear this mixture on and inside the chicken. Smear the oven bag with flour. Put the chicken in bag and tie the bag. Make a few holes on the surface of the bag with a needle. Place the chicken on a tray and put it in the oven preheated to 200°. When the chicken is roasted as brown as a berry, take it out from the oven. Rip the bag, take the chicken out and put it on a service plate.