Chilling of Eggs Inadequate in Laying Hen
Inadequate chilling of eggs may cause Yolk Mottled or Flecked Yolk, Yolk Cheesy or custard-like or viscous yolk and Watery White or White Haugh unit decreased (score should be 70 poor 50).
When a long storage period is needed for eggs (5 to 6 months), they should be held slightly above -2.8°C, the freezing point of the egg. While for the short-term (2 to 4 weeks) they should be held at 7.2°C.
The beneficial effect of low temperatures on albumen quality preservation has been known for a long time. It has been demonstrated that eggs held an average temperature of 16°C for 16 days had a Haugh unit value of 49 (high Haugh units indicate good albumen quality), while eggs stored at an average temperature of 10°C for the same period had a Haugh unit value of 69.
The whole egg contains about 75% of water; albumen has 88% and yolk 49%. Water loss can be minimized if the relative humidity surrounding the eggs is kept at or above 75%. Relative humidity of between 75 and 80% in egg storage rooms must be maintained to prevent moisture loss and an equal loss of egg weight. Relative humidity of 90% and above can cause mould growth, which in turn can penetrate the pores of the shell and contaminate the egg content. Mould growth appears first in form of white micelle (whiskers). At -6.7°C, in a moisture-saturated environment (100% Relative Humidity), mould can be expected to appear within 3 weeks.
Observed Clinical Signs Happenings
Internal Egg quality
- Yolk Cheesy or custard-like or viscous yolk
- Yollk Mottled or Flecked or Flaccid and Fragile (a very limited amount of mottling is normal)
- Watery White or White Haugh unit decreased score should be 70; poor <50
Chilling of Eggs Inadequate in Laying Hens DOES NOT show, exhibit or manifest any of the following clinical signs happenings:
- Egg drop
- Mortality above the standard
- Visibly sick birds
- Flock behaviour activity change
- Droppings abnormalities
- Respiratory abnormalities
- Neurological Nervous
- Lameness or unusual movements, incoordination, ataxia
- Eyes abnormalities
- Head, Comb, Wattles, Face, Nostrils, Sinuses, Mount, Beak, Earlobes, abnormalities (except eyes)
- Body Parts (Neck, wings, breast, abdomen, shanks, legs, hocks, feet, joints, vent, and skin, abnormalities), skinny body, retarded growth, weight depression
- Feathers abnormalities
- Feed Consumption Changes
- Diet or Feed Changes (Recent Feed delivery, Recent formulation /diet, Other silo or improper storage, another feed brand)
- Shell quality defects
- Causing Agents
- Inadequate chilling temperature and Relative Humidity storage of eggs
- Affected Systems/Organs
- Internal Egg Quality
- Mainly Affects
- Egg Quality Deterioration and Albumen (Egg white) and Yolk deterioration.
- Adequate temperature control and preservation of egg quality
- Suggested Actions
- Can be dealt with in house
- Technical assistance recommended
Impact on Egg quality
Impact on Liveability
Impact on Production
Overall Economic Impact
Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition. page 30
Donald D. Bell, Williams D. Weaver. 2009. Commercial Chicken Meat and Egg Production. Fifth Edition.