Used to make mineral blocks, calcium carbonate, is a valuable source of calcium. One recipe is given by Scoble in the Complete Book of the Budgerigar:
10 parts grit
2 parts bonemeal
3 parts ground charcoal
1 part ground rock salt
1 part ground cuttle bone
Add three parts of the above mixture to one part calcium carbonate. Add enough water to the completely mixed dry ingredients to form a thick paste. Place in trays or paper cups and allow to set. A wire or clip should be placed in the mix before it sets. The block might take up to 21 days to set.
Calcium gluconate has been used by breeders to cure and prevent egg binding in the laying hen and calcium deficiencies in chicks. Hens that seem to have trouble laying are given a small quantity in the water. Calcium gluconate also may be added to the nestling mix.
Calcium propionate is a very useful substance for all aviculturists. It is a preservative and is added as one level teaspoon to one pound of dry ingredients of nestling or hand rearing foods. Calcium propionate may also be used on fruits, vegetables, sprouts and soaked seeds. Some have reported that foods treated with calcium propionate do not spoil as quickly in hot and humid weather. It also can be used in the nectar and broth solutions for lories and hummingbirds.
Calcium propionate is used when sprouting seed. Calcium propionate will retard the growth of molds. Add 1 teaspoon of calcium propionate to 1 1/2 gallons of tap water. Add 3 pounds of seed. Allow the seeds to soak for 24 hours. Rinse with regular tap water and drain completely. Rinse with tap water and drain every 24 hours until the seeds sprout. The temperature must be at least 65 degrees for seeds to germinate properly.