Is my chicken done? How come it is still bloody?
Internal temperature is by far the most accurate way to gauge the doneness of any meat, poultry, or fish. Other indicators, like color or firmness, can also be helpful but are relatively unreliable.
Still, it can be unnerving to bite into a piece of meat that doesn't look done.
One reason chicken sometimes looks bloody even after it has been cooked to an internal temperature of 165°F (74°C) or more, is that marrow seeps out of the bones during the cooking process. (For a more complete discussion of this process, see http://www.hi-tm.com/Documents/Bloody-chik.html.)
This chicken is still healthy to eat and the flavor is not compromised in any way. In fact, overcooking chicken in an effort to minimize the "bloodiness" will only dry it out and make it less flavorful.
The most accurate way to gauge doneness in chicken is still to check the internal temperature near the center of the cut with a highly accurate thermometer (like those available on this site).
USDA and most chefs recommend about 165°F (74°C). If you remove the chicken from the heat at 160°F (71°C), it should reach 165°F (74°C) while resting.