Cracks in the egg shell form a risk for hatchability and chick quality. Both the strength of the egg shell as well as the handling of the eggs have an influence on the number of cracks. Although cracks can not totally be avoided, the total percentage should be below 0.5%.

It is important to know which part/s of the production process the cracks are caused, to be able to find and solve them.

The appearance and shape of the crack can already tell us quite a lot about the possible cause. When eggs are just produced by the hen, they are warm and wet, and the shell is very fragile. Only when the egg is dried up, the matrix shape of the shell becomes more rigid.

Cracks that are caused in the period directly after laying (within the first 10-15 minutes) will have a very fine, very dense structure, which appear very local (see pictures). When the cracks are caused later, the distance between the crack lines is much bigger and much more spread out.

When the majority of the egg shell cracks are indicating that the egg is cracked directly after its been produced by the hen, we obviously have to look in the laying nest as possible cause.

Possible causes:
- not enough litter in the nests
- too high bird density in the nests, not enough nests available
- part of the nests are not used, so overcrowding of certain nests
- not frequent enough egg collection
- egg belts too small, or not emptied often enough (automatic nests)