Frequently-used calcium sources feed for laying hens are generally stone powders such as calcite and limestone, calcium content of calcite and limestone are usually more than 33%, high-quality materials can reach to 35% -38%. Calcite color are commonly white or five-colors, limestone are in colors of light gray or light yellow in general. So calcite powder is called white stone powder while the limestone powder is called cyan stone powder.

What is the result of using poor quality stone powder in the feed producing? For example, a small scale feed factory reflected that laying rate of hens decreased by 1/3 when fed by the feed they produce. Detection found that the calcium content is 1/3 less than the standard, and further found that the calcium content of stone powder is only 22%, 1/3 less than the general stone powder with calcium content of 35% -38%, by testing the stone powder, it is judged to be dolomite.

Calcium content of dolomite is 22%-24%, the magnesium content reach up to 10%, excessive magnesium content would affect the absorption of calcium, ferrum and copper, so the dolomite is not suitable for being calcium source feed for laying hens. Dolomite is generally white, and the calcite is also white. If dolomite is used as calcium in the production, it would cause short of calcium content, leading to the decrease of laying rate.

Fineness of stone powder pulverization should be coarse or fine? Stone powder for laying hens should not be pulverized too small, the small granule calcium will stay for little time in muscular stomach, use ratio is low, leading to the eggshell quality reduction. Studies have shown that the stone powder used in laying hens diets generally requires to be the granulate coarse stone powder mixtures of no more than 15% of the 12 mesh standard sieve, and no more than 30% of the 16 mesh standard sieve.

Can zeolite powder being used as stone powder? Zeolite is an aluminosilicate mineral, containing more than 20 kinds of elements, multi-hole, strong adsorption. With functions of bacteria inhibition, growth promotion, reduce the faeces odor, it can be used as additives. But since calcium content is only about 2%, it can’t be used as calcium source feed instead of the stone powder  , otherwise it will lead to a serious shortage of feed calcium. In addition, medical stone and sepiolite are similar to zeolite, they should be separated from stone powder, farmers should improve the ability to detect and avoid misuse.

Laying hens eat stone powder for the aim of supplementing calcium and phosphorus and regulate the normal function of the body. How to master the functions and addition amount of stone powder in the laying hens feed? Stone powder for the laying hens feed can help increase the calcium content of the body, which is helpful to the eggshell forming; increase the friction between materials and easy for further absorption. By statistics, egg shell quality is better when granular coarse stone powder is used, broken eggs, soft eggs are less, the incidence of flock paralysis is reduced by around 0.5%.

Chicken feed customization experts said that in order to meet the demand for calcium nutrition for laying hens growth and laying period, stone powder dosage is about 1% to 2% in daily meal in for pre-laying period, and 7% to 8% for laying hens, as for concentrated feed, stone powder content should be 7% for young chicken and 20% to 25% for laying hens.

Stone powder added in the feed should be decided by its calcium content and solubility, but also affected by other feed calcium content. Quality of feed can not be simply judged by the stone powder content, such as the use of more high calcium low phosphorus meat and bone meal, the amount of stone powder in the feed will be reduced, while the meat and bone meal contains more harmful bacteria, easy to cause refractory diarrhea flocks, rarely added in the feed at present, so calcium supplementation in feed is mainly stone powder.

The followings are the matters and attention when using stone powder at production:

1. The older the hens, the lower their digestion and absorption rate, stone powder should be added appropriately;

2. Hens with intestinal digestion problem should improve the intestinal tract firstly;

3. Hens with tibial length do not reach the standard in the breeding period should pay attention to the calcium reserves in the expected date of confinement;

4. Feed intake is low in summer, stone powder should be added appropriately;

5. Any recommended formula is for reference only, do not blindly copy.