You cut into your fully-cooked chicken and see pink. Panic time? Throw it back in the oven? Not necessarily.
The Kitchn reminds us that when all parts of the chicken have reached at an internal temperature of at least 165F (74C), it's safe to eat, regardless of colour:
The USDA further explains that even fully cooked poultry can sometimes show a pinkish tinge in the meat and juices. This is particularly true of young chickens whose bones and skin are still very permeable. Pigment in the bone marrow can colour the surrounding tissue and make the bones themselves look very dark. Hemoglobin in the muscles can likewise react with air during cooking to give the meat a pinkish colour even after cooking. The chicken's feed and whether it's been frozen can also affect the final colour.
We've probably all been warned to stay away from pink poultry meat thanks to salmonella concerns, but your thermometer, not your eyes, are the best guide. That said, if you're not cooking and taking the temperature of the meat yourself, it's probably best to avoid pinkish poultry.
Chicken Still Pink After Cooking? Don't Panic [The Kitchn]