Choosing a good calcium source generally uses limestone, shells, etc. as the main source of calcium, but the proportion should be appropriate, and the ratio of stone powder and shell powder should be 2:3. With feeding 1% bone meal, the strength and smoothness of the eggshell are the best.
Calcium-supplementing time is suitable for laying-up laying ducks. Eggs begin to be laid around the age of 100 days. The best time to start calcium supplementation is 15 weeks of age. Calcium should be between the young duck and the laying duck, with an appropriate rate of 2.5%, and gradually increase thereafter.
The best calcium supplement particle calcium particles stay in the digestive tract for a long time, in the eggshell formation phase can be evenly fed with calcium, at the same time, granular calcium in the stomach have similar grinding effect of sand, can promote the digestion and utilization of feed. Practice has shown that with 50% of the shells and 50% of limestone in combination, the duck can absorb calcium well.