A Family Guide To Keeping Chickens (41 page)

Eggshells vary from the darkest brown through to speckled, light brown, tinted, cream, white, blue or green – with several different hens you could produce a multicoloured egg-box. There is no difference in taste or nutritional value but many people prefer eggs of a certain colour.

Marans’ eggs

With several different hens you can produce a multicoloured egg-box

Colour is usually added at the end of the egg’s development – it can actually be rubbed off a newly laid brown egg. Shells are white inside, apart from the blue/green eggs where the colour goes right through.

Shell colour can vary depending on the hen’s breeding strain, and often fades as the laying season progresses, especially if the hen is a good layer. Other reasons for loss of shell colour may be poor nutrition, stress, hot weather, age, disease or parasites.

A hen’s ear lobes can give an indication of shell colour – white lobes generally mean white eggs and red lobes signify brown eggs. However, there are several exceptions.

White ear lobes often indicate that the hen will lay white eggs

Whatever colour the shell, its purpose is to protect a developing chick. It is mainly composed of calcium carbonate and is surprisingly strong.

The shell is porous to allow it to ‘breathe’ and to lose moisture as the chick grows. On a newly laid egg the cuticle covering the shell is often damp but quickly dries to a protective sheen. Washing removes the cuticle and can allow bacteria to enter.

Soiled eggs can sometimes be cleaned by brushing gently with an old toothbrush. If washing is essential, use water slightly warmer than the egg. This will make the shell membrane expand and block the pores. Cold water will shrink the membrane and draw in bacteria. Eggs that have required cleaning should not be offered for sale.

Clean nest-boxes help prevent soiled eggs

It’s better to keep eggs from becoming soiled in the first place. Make sure nest-boxes are clean and prevent hens from roosting in them. Try to keep the area surrounding the henhouse dry so the hens don’t bring muddy feet into the nest-boxes. Collect eggs regularly, making sure the container and your hands are clean.

The eggshell is lined with an outer and inner membrane, incorporating an air space, which is usually located at the wider end of the egg. As the egg ages, moisture is lost and replaced by air – the warmer and drier the atmosphere, the faster this happens. The height of the air space indicates the age and quality of an egg.

In a fresh egg you can easily see two kinds of albumen (white) – a thin outer layer and a thick jelly-like layer around the yolk. As the egg ages, all the white becomes watery. Watery whites in fresh eggs may be due to hot weather, the age of the hen or exposure to disease, such as infectious bronchitis.

If the egg is very fresh you may see the chalazae – white string-like substances that hold the yolk in place. These disappear with storage and don’t affect the taste of the egg.

In the middle of the egg sits the prize – a golden yellow yolk. The colour comes from greens (especially grass) in the hen’s diet, although there are feeds which include artificial colour enhancers. Chickens free-ranging on grass in summer will produce yolks of a colour and flavour undreamed of by battery hens. Greenish yolks can be caused by the hen eating acorns or weeds like shepherd’s purse.

On the edge of the yolk is the germinal disc – a small white spot containing a single female cell. If the egg is fertile, this spot will be larger and rounder. Fertile eggs are fine to eat as long as incubation hasn’t started, in which case red veins may be seen when the egg is broken. This can happen within a couple of days if the eggs have been sat on by a broody hen or are left in very warm conditions.

Finding Alien Eggs

Funny things can happen during the egg’s long journey to the outside world. Some are just glitches in the system, although odd eggs may occasionally indicate a problem.

Sometimes a mini egg appears, usually without a yolk.

This is often caused by a piece of tissue that has separated from the ovary and been encased with egg-white and shell. It is quite common with pullets or older hens at the end of their laying season and is usually nothing to worry about.

These little eggs have many names: witch eggs, fairy eggs, wind eggs, cock eggs – the last because it was once believed that they were laid by cockerels!

Sometimes more than one yolk is released during production – either together or in quick succession – and they become enclosed in one shell. Multiple yolks are more likely in pullets, although this can also be an inherited feature.

Double and triple yolks are fairly rare – nine yolks in one shell is claimed to be the record.

These eggs are likely to be larger and there may be blood on the shells. If a hen frequently lays huge eggs, it’s worth checking that she hasn’t suffered any internal damage.

It is very rare for eggs with multiple yolks to hatch as there isn’t room for two chicks to grow in the same shell.

Sometimes you pick up what looks like a normal egg, only to find a jelly-like substance without a shell. I hate this! Or the shell may be wrinkled or very thin. These shells, or lack of them, can encourage egg-eating so they should be taken away as quickly as possible.

An occasional shellless or wrinkled egg may be the result of a sudden fright. Shell problems can also be due to age – pullets starting to lay or older hens at the end of their laying years. Shell quality sometimes deteriorates as hens start moulting.

If there isn’t an obvious cause, and the situation doesn’t resolve itself, then further investigation might be needed. Dietary imbalance, stress or disease can affect shell quality:

Wrinkled shells

It shouldn’t be necessary to give extra calcium if the hens are eating a good layers’ feed and have access to soluble grit – an excess of calcium can cause health problems. A better plan is cutting out treats to make sure the hens are eating properly. Check they are getting enough vitamin D, which enables the utilization of calcium. Feeds should contain vitamin D but it is also obtained from sunlight. Cod liver oil can be given as a supplement to hens kept mainly under cover.

Hot weather can result in hens eating less food. Make sure they have access to shade and cool water.

Occasionally a hen is unable to process calcium properly but veterinary advice will be required to establish if this is the case.