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By Katie Thear

Here is a list of the main problems that can manifest with eggs.

Wind egg

This is a small egg with no yolk. It is fairly common when a pullet is first coming into lay. It is not important and can be ignored, unless the pullet continues to lay such eggs. Wind eggs can also occur in older hens if they are subject to sudden shock.

Greenish yolks

Acorns and the annual weed shepherd’s purse can both have the effect of turning the yolks green. Check the pasture and rake if necessary.

Eggs with pale yolks

Yolks are naturally paler in winter when the grass is not growing and there is nothing wrong with this. Customers prefer deeper yolks, however, often having the erroneous perception that such eggs are more ‘free-range and natural’. In fact, battery egg producers routinely give their birds feeds that contain artificial colouring agents to make the yolks deeper. More natural feeds contain grass meal and maize to improve the colour.

Eggs with vivid orange yolks

Too much yolk colour pigment in the feed, either artificial or natural. The Roche scale is the standard way of determining degrees of yellow-orange in the yolk.

Double-yolked eggs

This is fairly common with large eggs and is not a problem except where fertile eggs for incubation are involved. It is caused when two yolks are released into the oviduct at the same time and are then encased by one shell. It can also be caused by a sudden shock.

Egg with blood on the shell

This is often the result of straining on the part of the hen, where large eggs are involved. It may also be the case with a pullet first coming into lay. Avoid giving pullets too much artificial light until they are well grown before the commencement of lay.
If the shells have small spots of blood on them, rather than streaks, then suspect the presence of red mites. Treat with an anti-mite preparation from the vet or specialist suppliers.

Egg with blood spots inside

This is usually the result of blood escaping from the ovarian follicle and becoming embedded in the albumen. It can sometimes be the result of shock or stress and normally rights itself. There is some evidence that there is a hereditary tendency for this condition, so avoid breeding from such a hen.

Dirty eggs

The solution to this problem is obvious! Nest box material needs to be checked frequently and soiled material removed. Every effort needs to be made to stop the foraging area becoming muddy otherwise it is carried in on the hen’s feet to be transferred to the eggs. Ensure that eggs are collected frequently.

Fertile eggs

If hens are running with a cock the chances are that they will be laying fertile eggs. These should not be offered for sale for they cause offence to many consumers. Registered producers are required by the egg marketing regulations to produce eggs with, ‘a yolk that is free of foreign bodies’.

There is considerable misconception about this subject, with people making varied claims such as: ‘hens lay better when there is a cock with them’, and ‘fertile eggs are more healthy and nutritious’. In fact, the opposite is the case with both claims. With the former, there is a greater risk of disease transference, as well as physical damage to hens from the male’s spurs. With the latter, there is a greater risk of disease-transference into the egg.

Traditionally, breeding flocks and laying flocks were kept quite separate, as they still are with free-range flocks today. If you have your hens running with a cock and don’t object to eating fertile eggs, that is of course your own business, but selling them to others should be avoided.

Soft-shelled eggs

The first pullet egg may be soft-shelled until her system gets into its stride. If it continues, make sure that the birds are getting a balanced diet such as that provided by a commercial free-range or organic layer’s ration. Such feeds will usually contain calcium and phosphorus in the right ratio (around 3.5-4% calcium to 0.3% phosphorus). Providing a little crushed oyster-shell or calcified seaweed will ensure that any deficiency is rectified, for the birds will not take more than they require.

A shock can also make a hen lay a soft-shelled egg. My own observations are that if a flock is caught in a sudden shower of rain (for they are sometimes too dim to run for shelter), a few soft-shelled eggs are often produced the next day, but by the following day, they’re back to normal.

It is when soft-shelled eggs or misshapen ones are produced regularly that there need be a cause for concern. Veterinary advice should be sought. Conditions that adversely affect eggs include Newcastle disease (a notifiable disease to the authorities) and Infectious bronchitis, but there would be disease symptoms showing in the birds themselves if either of these was present. Hybrids are normally vaccinated against them.

Egg drop syndrome (EDS) is also a viral infection that results in a reduced number of eggs, as well as an increased number of pale-shelled eggs. Birds do recover from it but egg production may not get back to its previous level and there may still be a proportion of deformed ones produced. It can be vaccinated against.

Dark shells becoming pale

Shells that are normally dark brown may become lighter for a number of reasons, including stress, illness or lack of appropriate food. The main reason, however, is strong sunlight on the back of the hens. Ensure that there are enough shaded areas for them on their ranging area.

Eggs with watery albumen

This is more common in hot weather than at other times of the year. It is also more frequent in older hens. Occasionally it can be a reaction to vaccination. In this case, a multi-vitamin supplement in the water can help. Infectious bronchitis, referred to above may also be the cause in an unvaccinated flock. If the condition persists, veterinary advice should be sought.

Middle-banded egg

A sudden shock can cause a temporary halting within the egg-laying system. If there is an egg there at the time, it may end up with an extra band or ridge around it. They are normally nothing to worry about, as long as the flock is not subjected to regular disruptions.

Misshapen eggs

These differ from middle-banded eggs in having a range of distortions, including soft ends and uneven or ribbed surfaces. Thin patches or excessively chalky areas may also be seen. They are more common with older hens, but may also indicate a disease such as Infectious bronchitis or egg drop syndrome (either present or past). If the condition persists, veterinary advice should be sought.

There are obviously quite a few things that can go wrong with eggs, but it is also worth pointing out that it is a minority of eggs and chickens that are affected by problems. If chickens are well-fed and housed, in clean conditions and with access to plenty of fresh air and good ranging space, they are likely to remain healthy and productive for a long time.

Copyright © Katie Thear 2005