COOPERATIVE EXTENSION SERVICE . DEPARTMENT OF ANIMAL SCIENCES . PURDUE UNIVERSITY
poultry for profit
P-93
October, 1970
Are Cracked Eggs Costing You Money?
Joe G. Berry Extension Poultryman
Ways to Reduce Cracked Eggs
1.	Gather eggs often.
2.	Handle eggs with care.
3.	Be sure adequate calcium, other minerals and vitamins are added to the ration.
4.	If automated equipment is in use, be sure that it is operating properly.
5.	All of these factors can be included in one item GOOD MANAGEMENT.
Once simply a supplier of nutrients and protector of developing chicks, the egg fills a much more complicated role today. Since man has used the egg as food, he has found that it was not designed to withstand the multiple handlings it receives on the way to his dinner table--and often cracked shells become a major problem.
Solving the problem is not simple, since making the shell thick enough and strong enough for man's handling would hamper the baby chick in its development. Since it seems that the egg is destined to continue in its dual role it is likely to continue to fall short of the standards imposed upon it in both cases.
However, there are some steps which can be taken to improve the shell cracking situation.
To understand the shell cracking problem, a look should be taken at the shell formation process. The entire problem cannot be traced to the formation of the shell, but some improvement in the process can be of value later.
The formation of chicken eggs involves several steps, one of which is the development of the egg shell. This particular step takes place in the uterus and requires about 15 hours to complete. Here the calcite, a crystalline form of calcium carbonate, is deposited on the egg.
The immediate source of the calcium is the blood, but the ultimate source is the chicken's food. However it has been demonstrated that during the period of shell formation, the hen is unable to absorb enough calcium to meet the full requirements of the shell secreting glands, no matter how much calcium is fed. When the rate of absorption from the gut falls short of the rate at which calcium is removed from the blood by the shell secreting glands, the deficit is made good by the liberation of calcium from the skeleton.
The removal of bone calcium for the egg shell increases as the dietary supply of calcium decreases, and if no calcium is supplied in the feed, all the shell calcium
Cooperative Extension Work in Agriculture and Home Economics, State of Indiana, Purdue University and U. S. Department of Agriculture Cooperating. H. G. Diesslin, Director, Lafayette, Ind. Issued in furtherance of the Acts of May 8 and June 30, 1914.