Hartz® Cuttlebone with Holder For All Pet Birds. Natural way to keep beaks trimmed. Great source of calcium. Hartz® cuttlebone with holder supplies a natural source of calcium and helps keep your bird's beak trimmed and sharpened. Maintain a clean cuttlebone in your bird's cage at all times. Guaranteed analysis. Calcium (minimum) - 33%. Calcium (maximum) - 38%. Phosphorus (minimum) - .03%. Hartz is a trademark of The Hartz Mountain Corporation. www.hartz.com.