The physical appearance of eggs is a determinant factor of egg’s market value because consumers may think that such eggs are not produced in a hygienic environment and probably unfit for human consumption.
The following are seven possible causes of pale eggs in poultry:
- Parasite Infestation
Infestation with endoparasites like capillaria and round worms may cause pale shell and pale yolks due to damage of the intestinal wall, reducing nutrients absorption necessary for egg development. That is why farmers must deworm and delouse their flock 3-4 times in a year to eliminate parasites.
Viral diseases like Newcastle disease, Mycoplasma infection and infectious bronchitis damage the oviduct and affect egg production. The viruses directly infects and damages the reproductive tract which manifests indirectly in the product of the tract, the egg numbers decline, eggshells become thinner, abnormally pale and have irregular contour. It also affects internal quality of eggs and the problems can persist for a long time.
The colour of eggs is genetically determined, but within a strain and flock there is always some variation.
Colour of eggs produced by older birds becomes pale as they grow older, egg size increases with age and the same amount of pigment is dispersed over a larger surface area. In older birds it is normal for the tapered end of the egg to contain less pigment than the rounded end.
It has a very little effect on shell colour but nutrient deficiencies can influence the total process of eggs development, including the shell.
- Chemotherapeutic Agents
Sulphonamides and Nicarbazin are drugs that can lead to production of pale eggs. Ingestion of high doses of chemotherapeutic agents can results in white eggs within 24hrs.
The bulk of the pigment is transferred to cuticle about 4 hours before laying. Stress like handling, vaccination, loud noises, high stock density etc can cause a delay in oviposition and the cessation of shell gland cuticle formation. Stress interferes with the ability of the epithelial cells in the shell gland to synthesize the cuticle will affect the intensity of eggshell pigmentation.