Clean, wash and chop the soup vegetables. Dice bread. Wash liver, dab dry, also dice. For the filling, press the sausage meat out of the skin into a mixing bowl. Add 1/3 of the soup vegetables, liver and bread cubes, season with salt and pepper.
Knead with the dough hook of the hand mixer. Wash the pheasant, dab dry inside and outside, rub with salt and pepper. Put the filling into the pheasant, close the opening with wooden skewers and tie up with kitchen string.
Put the pheasant on the fat pan of the oven, cover with bacon and roast in the preheated oven (electric: 175 °C/ gas: level 2) for 50-60 minutes. In the meantime, peel and finely dice the onions.
Heat the oil in a pot and fry the onions until transparent. Add remaining soup vegetables and lentils, deglaze with vinegar and stock, simmer for 15-18 minutes. Season to taste with salt, pepper and sugar. Arrange pheasant and lentil vegetables on a plate and serve garnished with parsley and thyme as desired.