Well a Dr. O. Peter Snyder of the Hospitality Institute has addressed the problem with a testing series along with photos. His conclusion: “According to the poultry industry, today's marketed chickens are considerably younger.” “Their bones have not yet matured and are still somewhat soft and porous. As a result, there can be seepage of bone marrow through the soft bone and into the surrounding meat.”
"When a young chicken is deep chilled, frozen ice crystals form inside the bone. They expand and force the heme out of the marrow through the soft, porous bones. During the cooking process, the tissue will darken in color. Although the appearance is unappetizing, the meat is not harmed when this happens."
“The retail food industry is being forced to sell grossly overcooked chicken in order to get rid of the red blood color around the bones. The result is chicken that is dried out.”
Click the link to Read the whole article: . Bloody Chicken