Calcium in the Avian Patient
The most widespread mineral in the body, calcium is required for normal metabolism and bone mineralization.
Physiology
Calcium homeostasis is under the control of calcitonin, which is produced by the ultimobranchial gland, vitamin D, and parathyroid hormone. In laying hens, most dietary calcium is used for egg production. Rising estrogen levels promote increased intake of calcium supplements like cuttlefish bone and calcium-rich foods, however the quantity of calcium ingested daily is insufficient for the massive deposition of calcium required for eggshell calcification.