Slice and lightly saute the mushrooms. Set aside. Prepare the wash by combining the egg whites, milk, salt and pepper. Set aside. Place the chicken breasts on your cutting board and on one breast, place the sauteed mushrooms and feta cheese until it is completely covered. Flip the opposite breast on top of the mushroom-and-feta-cheese-covered breast creating a sandwich of chicken-stuffing-chicken. Now, wrap the folded chicken breasts in bacon until it is completely covered and there are no visible holes for the stuffing to seap out in the cooking process. After the breasts are completely covered, roll it in the flour and then dredge it in the egg wash before returning it to the flour. Place your fryer basket completely in the oil, and slowly place the breast in the oil. Cook for approximately 10-15 minutes until cooked all the way through, continually flipping the breast in the fryer basket every 2-3 minutes. Set aside to cool for 2-3 minutes, and cut into slices and serve with your favorite side items.