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Hairline cracks
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Hairline cracks
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Hairline cracks are barely visible, thin cracks in the eggshell, which are caused by rough handling (transport, mechanical shocks, rough handling by staff). The eggshell is often of inferior quality to start with, and the impact of vibrations or other mechanical shocks can cause ruptures and cracks. This can soil the suction cups on the candlingtransfer system and make other eggs dirty, or interfere with the working of the suction cups. Setting eggs with hairline cracks reduces hatchability and chick quality, as the damaged eggs dehydrate more easily and there is a higher risk of infection. Eggs with hairline cracks can cause as many problems as eggs with more serious shell damage. The hatchability of these eggs is at least 25% lower than intact eggs. There is also a greater
What do you see here? risk of contamination because pathogens pen-
The eggs are visually checked for cracks. Only the outer shell is dam- etrate the shell. As a result, mortality up to two aged, but the shell membranes are usually intact. You can recognise weeks of age is four times higher among chicks hairline cracks by a faint grey line on the eggshell surface. hatched from eggs with hairline cracks than those from intact ones. In most hatcheries, random sampling of eggs (450 to 600 eggs) for hairline cracks is done using a company-specific protocol. The results are comPoorer results for all aspects municated to the breeder.
Characteristic Good quality eggs Hairline cracked eggs
Hatchability • Eggs set • Fertile eggs 74.4% 80.9% 50.5% 56.4% Chick weight 45.0 g 43.5 g Chick mortality 2% 7.5% Egg weight loss in setter 13.4% 17.0% Embryonic mortality • Early • Mid • Late • Cull 7.9% 0.0% 4.6% 5.3%
copyright protected 13.9% 2.9% 15.5% 6.2%
Contaminated or broken 1.2% 5.2%
Hatching eggs with hairline cracks have a poorer performance for all aspects above. This applies to results at hatch, and to the performance of the chicks later as broilers (higher mortality, lower chick weight). Candle the egg to make identifying hairline cracks easier.
