Managing key pullet, layer gut health challenges

Learn how addressing a combination of feed, farm and health issues can help to ensure that pullets and laying hens are prepared to overcome challenges and thrive.

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Optimal pullet management requires consideration of feed, farm and health. Courtesy Trouw Nutrition
Optimal pullet management requires consideration of feed, farm and health. Courtesy Trouw Nutrition

From early life through extended lay, hens typically experience common gut health challenges that can reduce egg production and producers’ economics.

To ensure that layer health and productivity are not compromised, producers need to focus on health, nutrition and farm management strategies.

There are three key periods when producers should place an extra focus on health, nutrition and farm management.

Key challenge periods

Weeks 3-8: During this period most pullets will experience a coccidiosis challenge, which can be complicated by necrotic enteritis. Immunosuppressive challenges may also occur, for example, from infectious bursal disease virus or chicken anemia virus, affecting vaccination success and increasing pullets’ susceptibility to necrotic enteritis outbreaks.

Anecdotal reports from veterinarians note that while viral enteritis has traditionally been associated with broiler production, its adverse effects also can affect pullet growth and uniformity.

End of rearing/start of production: As egg production begins, multiple stressors may threaten hens’ intestinal health. Feed changes, transport to the layer house and new housing all impose stress.

During the first few weeks of lay, hens’ hormonal changes trigger a period of immunosuppression. Often, a hen is challenged to overcome a small to moderate coccidiosis challenge until her immune system is returned to full capacity.

Following start of lay: Focal necrotic enteritis (FNE), also known as "gray gut" or focal necrotic duodenitis, is a prevalent, but severely under diagnosed and poorly understood, disease in laying hens. It usually occurs between 20 and 30 weeks of age, but in some cases remains for the full production cycle.

Mycotoxins are a consistent challenge spanning all phases of a hen’s life. They can harm gut integrity, suppress immunity and reduce performance. Both short exposure to high levels of mycotoxins as well as sustained exposure at lower levels should be avoided.

Pullets and layer gut health challenges are complex and often multifactorial. Applying a strategy that addresses the management of feed, farm and bird health is essential to achieving persistent layer and breeder flocks.

Focal Necrotic Enteritis Compilation

While symptoms of FNE typically present sub-clinically in production environments, its presence can be revealed during analysis of the gut and crop contents. Courtesy Trouw Nutrition

 Health Strategies

Most pullets are vaccinated against coccidiosis, however, while vaccines against coccidiosis are highly effective, their protocol requires more attention compared to other vaccinations.

The young pullet needs repeated exposures to the vaccine strain, that is only applied once, to effectively develop immunity. This is a major difference compared, for example, to the easier application of live respiratory vaccines.

Several factors have been shown to delay or even stop the process of coccidiosis vaccination.

Controlling relative humidity, especially in the first few weeks of life, is important for supporting vaccine success. But week one Escherichia coli challenges, (subclinical) immunosuppressive diseases and any gut health challenge can disrupt a coccidiosis vaccine’s success as well.

Fortunately, monitoring coccidiosis vaccination uptake and cycling is easy and provides good insight to optimize vaccination and management procedures.

Nutrition strategies

Classic necrotic enteritis is usually found together with coccidiosis outbreaks by Eimeria field strains. Eimeria maxima, E. brunetti and E. necatrix, in particular, have the potential to cause significant morbidity and even mortality.

In more severe cases involving necrotic enteritis and coccidiosis field strain challenges, veterinary intervention through treatment against either Clostridium perfringens (the agent responsible for necrotic enteritis) and/or against coccidiosis may be necessary.

After experiencing these challenges, pullets need additional time and nutrition resources to recover and catch up on growth and development. The correct choice of diet and feed additives can help in both preventing and recovering from health challenges.

Trace minerals are a good example of how the source of supplementation can support performance. Research conducted at the Bangkok Animal Research Centre, Thailand, has found that supplementing diets with hydroxy trace minerals, for example, can increase pullet uniformity. This effect may be due to their increased bioavailability.

Although FNE rarely causes mortality, it is a chronic disease that affects production efficiency and is frequently responsible for increased feed consumption as hens eat more to compensate for nutritional losses and malabsorption. In other cases, egg weights are below the standard, and production tends to be lower (1%-10%).

Clinical signs are hard to spot, but a trained poultry specialist will be able to notice abnormal crop filling (watery contents with some coarse particles), slightly depressed behavior, early signs of poor feathering and a lower wing tension. Typically, some droppings will contain undigested particles and too much water.

Treatment with antibiotics will usually provide relief from FNE only for the duration of treatment and relapses are very common. As such, FNE is far more challenging to manage than the earlier discussed classic necrotic enteritis in pullets. Additionally, research is problematic as researchers have been unable to reliably reproduce FNE in experimental conditions.

Farm strategies

The role of the farm manager and visiting veterinary and technical staff is critical for timely and effective prevention and management of gut health challenges.

Contrary to broiler production, where sub-optimal gut health almost guarantees production efficiency losses, pullets and laying hens have a spectacular potential for recovery.

Keeping a sharp eye on flock weight, flock uniformity and feed intake, as well as regular checks on gut health through necropsies and use of diagnostics tools to look at coccidiosis are helpful in making the best management decisions.  

Anticipating developmental challenges, applying an integrated approach including feed, farm and health management; and tailoring interventions to the specific challenge can support the development of pullets and will optimize performance and persistence of laying flocks.


Great layer performance starts in the pullet house

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