The Myoglobin in meat, the stuff the makes the meat and the juices Red, is the Protein that holds Oxygen in the muscle of animals. There is lots of Myoglobin in active muscles, Beef walk around, and little in inactive muscle, pen bound Pigs and Chicken Breast as they can't fly. Myoglobin is not the same as Hemoglobin the red protein that carries Oxygen in Blood. Commercially slaughtered animals are all bled out after stunning removing the blood.
Anywho, the Myoglobin begins to loose it's red color and starts to turn Brown at around 150°F and is completely brown and coagulated at 160°F. If you cook your bird to 160-165°F in the Breast there will be no red anything. The Legs are a slightly different story. A) The Legs contain more Myoglobin. B) Legs have big bones that do not absorb or conduct heat well. What this means is although the bulk of the leg meat will have juices that are no longer red at 165°F, the meat closer to the colder Bones and Joints has not yet reached 165°F and you see Red Juices. Because of this difference, if you read any of the Chicken/Turkey threads you will find they recommend Smoking/Cooking your Poultry until the Internal Temperature (IT), measured with an Accurate Thermometer, reads 165°F in the thickest portion of the Breast and 175-180°F in the thiickest meat of the Thigh. Following this guideline will Guaratee you will never see Red in your Birds again.
Now just to mess with your head...
...Depending on your Smoker, if you burn Wood, Charcoal or Gas, the Nitrogen Dioxide released from the burning fuel will keep some of the Myoglobin from turning brown. You will follow the above guidelines, cut the meat up and see Pink Meat making up the surface 1/4" of meat. The meat is fully cooked but the Pink is still there. It's called a Smoke Ring. A similar reaction takes place when meat is Cured with Sodium Nitrite ( Cure #1) . The difference is " WE WANT " Pink meat after the meat is cooked. Cure #1 is what makes Smoked Ham, Hot Dogs, Bacon and Kielbasa stay Pink no matter how long you cook it. Soak your Turkey Legs in a Curing Brine and even if you cook to 175-180°F, the meat will stay pink right to the bone. However it is cooked and it will be tender, smokey and juicy with a Hammy flavor that Fair goer's prize.......After they try to return them for being RAW and are told they are Supposed to be Pink.
....Good luck and Welcome to the SMF Family...JJ