Cut the poulard into four parts. Peel and halve the onions.
Dice the bacon and leave it in a large roasting pan. Add 40 g of fat and fry the poultry parts vigorously on all sides. Add the onions and brown them briefly. Peel garlic, chop and add. Add brandy, salt, pepper, bay leaves and wine. Cover and braise for approx. 40 minutes.
Briefly wash, clean and halve the mushrooms. Heat the rest of the fat in a pan and steam the well drained mushrooms for about 3 minutes. Season with thyme and add to the poultry. Tie the stock with a sauce thickener and season to taste. Scatter thyme leaves on top.