Chicken Blakcberry Vinegar

—BLACKBERRY VINEGAR—
1/2 cup blackberries
1 cup vinegar, white

—CHICKEN—
2 each chickens, halved
6 oz vinegar, blackberry
12 oz demi-glace
6 oz butter

—DEMIGLACE—
5 pound beef, bones
5 pound chicken, bones
1/2 each celery, bunch
1 each carrot, medium
2 each onions, medium
1 each bay leaf
4 each garlic, cloves
1 each thyme, pinch
1 cup tomato, puree

Blackberry Vinegar: Soak the blackberries in the vinegar for 3 hours, then pass the mixture through a food mill. Discard the seeds. Chicken: Saute the chicken and then remove it from the pan. Drain off the fat and deglaze the pan with blackberry vinegar. Add the chicken and demi-glace. Bring to a boil. Finish with butter. Remove chicken to serving plates and cover with sauce.