The tarry black is from blood in her system. If at all possible, you should get some of the Kaytee OR just take some of her chick crumbles, wet them down into a mush with the medicated water/electrolytes and give that to her via syringe so she gets some much needed energy. High protein foods like egg yolk assist the cocci in multiplying, so while medicating for cocci, keep them off these kinds of foods. Since she is still alive, she probably has a chance to survive, but will take a lot of hands on care for a little while - feeding small amounts via syringe at least every 3 hours round the clock.