Egg production problems

Problems with egg production, often coupled with shell quality problems, are not uncommon and are a real worry to the egg producer as these problems often result in severe financial loss. There are many factors which can influence egg production and shell quality. This article will highlight some of the possible causes of production problems in the free range layer. Further articles will discuss some of these individual problems in more detail.

Rearing problems

Disease problems in rear with viral or chronic bacterial infections or parasitic problems with coccidia or worms may result in poor performance in lay. If pullets are underweight for any reason at transfer to the laying site, this will influence production. Sudden changes in light programmes between rearing and laying site can also create production hiccups.

Infectious agents which may cause production or egg quality problems

Viral infections – Many viral infections can cause production problems, sometimes coupled with mortality in laying birds. These include Newcastle disease, Infectious Bronchitis and IB variants, Infectious Laryngotracheitis (ILT), Egg Drop Syndrome, Epidemic Tremor, Avian Influena and Avian pneumovirus (TRT).A good vaccination programme should protect layers against the majority of these viruses. Good administration of vaccine is critical for success and it is a good idea to check birds' response to vaccination by taking blood samples from the flock.

Blood samples taken at 14-16 weeks of age can be used to assess the efficiency of response to live vaccine. Blood samples taken after transfer to the laying site show the response to inactivated vaccines at transfer and give a good audit of the rearing vaccination programme. If mortality or an egg drop problem occur, blood samples taken immediately and then 2-3 weeks later, during the recovery phase, can be used to compare with earlier blood sample results to look for any rise in antibody levels which would suggest viral challenge. This approach helps to pinpoint which virus or viruses may be involved.

Bacterial infections which can cause problems include Mycoplasma, both Mycoplasma gallisepticum and Mycoplasma synoviae, Pasteurella multocida, Erysipelas, E.coli and spirochaete infection. Good biosecurity, coupled with good management, and vermin control will greatly reduce the risk of bacterial infections.

Parasitic problems – Parasitic disease with external parasites such as red mite or Northern Fowl mite and internal parasites, roundworms, hairworms (capillaria), coccidia, histomonas and trichomonas can all cause production problems and sometimes mortality. Good biosecurity, good pasture management, routine worming and treatment for mite as needed should help to reduce the risk of these parasitic diseases causing problems.

Environmental factors

· Fluctuations in feed or water supply, either due to interruption in supply or poor palatability can severely affect egg production.

· Sudden changes in lighting, either in the first period of light intensity can adversely affect production.

· Too high ammonia levels can reduce bird health and thus influence production.

· Stresses such as sudden disturbances eg aircraft noise, hot air balloons will upset birds.

· Environmental temperature. Very high environmental temperatures can depress feed intake and effect production.

What to do if you have an egg production problem?

First of all, double check figures have been calculated correctly. Are eggs being lost to the system in any way, eg increased floor eggs, egg eating, egg stealing? Are the numbers of birds in the shed correct?

If you establish that there is an egg production problem, this should be investigated in a systematic way. First of all, look at the flock for any obvious signs of disease. If the flock look sick, a post mortem examination is worthwhile to investigate if there is an infectious or parasitic disease problem. If the flock look well and healthy, there may be little benefit in sacrificing the birds for post mortem examination. Look at egg shell quality. If loss of shell colour or abnormal shells, may suggest viral challenge, in some cases parasitic disease. Blood sampling may be useful to determine if there is any evidence of viral or mycoplasma involvement. If there is nothing to suggest a disease problem, all aspects of the environment, feed and water intake should be assessed. If no obvious problems are found, it may be useful to look at a feed sample to see whether there is any problem with, for example, low protein or excessively high or low salt levels which might adversely effect egg production.

Disease, particularly viral challenges and feed problems, are often blamed for egg production problems although, in many cases, the causes are multifactorial and, in many cases, relate to environmental or management. Egg production problems is often a very confusing and frustrating problem to resolve but a structured and systematic approach to investigating such problems should help to pinpoint the most likely causes.