Declining day length

Hens are sensitive to day length, and particularly to the direction in which day length is changing when it comes to laying eggs. Declining day lengths discourage egg production. It is not unusual for a flock owner to have hens go out of production during winter months because the days are shorter.

A layer farmer can avoid this problem and maintain egg production year-round by using artificial lighting to give hens a long day length no matter what the season. Even in the middle of winter, if chickens are given at least 14 hours of daylight, they will lay every day except during moulting.


Moulting is the process of shedding and renewing feathers. It occurs once a year, usually during the change in season from summer to winter months as the day length starts to decline.

When hens have been in production for many months, they tend to cease laying eggs in order to allow a complete rest of the reproductive system as well as to revamp or replenish their body reserves. The process takes about a month.

It is a very important process but can have a negative effect on the profits of the layer farmer, especially if the hens are all moulting at the same time. However, if artificial lighting is provided, a hen may moult at any time of year and not in synchrony with other hens. If this happens, she should return to lay in a few short weeks without disrupting production too much.

Hen shedding feathers during moulting process.


A hen can live for many years. Much as in other species, an ageing hen eventually will lose her ability to be reproductively active and stop producing eggs. Birds that have gone out of production due to age must be culled promptly to prevent losses. These birds are sold as ex-layers to be used for meat.


Many poultry diseases affect egg production. Often the birds will show symptoms of illness, but sometimes they will not. If a disease is suspected, it is important to consult a poultry veterinarian without delay. A timely diagnosis may allow effective treatment for some diseases and a speedy diagnosis may prevent losses of whole flocks on a layer farm.

A number of bacterial diseases, viral diseases and even syndromes may have a negative effect on egg production and quality. They may cause a drop in number of eggs produced and also cause abnormalities in egg shells, consequently lead to production losses. Let us look at some of these diseases and syndromes and how best to prevent them:

Bacterial diseases such as septicaemic disease, chronic respiratory disease, and colibacillosis will result in a substantial drop in egg production and may lead to poor-quality eggs with abnormalities. Practising proper biosecurity and sanitation may help prevent these and other bacterial diseases.

Viral diseases such as infectious bronchitis (IB), egg drop syndrome (EDS), swollen head syndrome, avian influenza and Newcastle disease will all result in a partial to complete drop in egg production. Egg quality is also affected by thin-shelled eggs. Prevent these viral diseases by following a recommended complete vaccination plan.

Syndromes – Both fatty liver haemorrhagic syndrome (FLHS) and cage layer osteoporosis will affect egg production to some degree. While restricted feeding may be a solution for FLHS, adequate nutrition helps to reduce cage layer osteoporosis.

In conclusion, keeping a high and persistent production is the way to achieve success in poultry layer farming. The farmer must keep his birds healthy, well fed on nutritious feed, and also be able to provide and maintain an environment conducive to promoting egg production.

“Remember, more eggs more money!”

For more information, contact Barbara Mulonda Simbaya on or (+260)969-202-207.