Do you think this chicken is safe to eat?

The hiness is due to the chicken fermenting and therefore starting to spoil. I would have cooked it a day or two earlier if I were you. I, too, have a super cold fridge where I could get away leaving defrosted meat to be kept chilled for a day or two until I'm ready to cook it. Beef or other red meats tend to keep. Seafood and poultry I don't really mess with 3 or 4 days later.