As with any species, an adequate supply of vitamins and minerals is key for good poultry nutrition, strengthening the bird’s defenses against harmful pathogens. Nutrition becomes increasingly important after periods of disease or stress when the immune system is weakened and energy levels are at their lowest. In fact, nutrition is a crucial factor in preventing, treating or recovering from illness or stress.

There are many vitamins required for optimal poultry health. These can be classified as either fat soluble vitamins – A, D, E and K, for example – or water-soluble vitamins, such as riboflavin and the B vitamins. Usage of these nutrients in adequate amounts, as well as some others, can both improve animal health and the producer’s bottom line.

Supporting the skeleton  

Vitamin D plays a vital role in optimal function of a hen's skeletal system, strengthening the bones, claws and beak. It also has a positive impact on the quality of the eggshells produced by layers.

The amount of vitamin D a bird requires depends heavily on the intake and bioavailability of two other nutrients, calcium and phosphorous. Indeed, the vitamin D requirements of hens are increased by inadequate levels of these two nutrients. As animal growth and skeletal development is linked to all three, the producer must monitor performance closely, especially after illness, because vitamin D can affect the bird’s immune response. The consequences of vitamin D deficiency are serious, and include rickets, poor growth and a decrease in egg production.

Promoting growth  

Naturally occurring in green grass, alfalfa and some fish oils, vitamin A, otherwise known as retinol, is another nutrient essential for poultry health.

In poultry, a deficiency of vitamin A results in poor feathering along with droopiness, nasal and ocular discharge and eye lesions. Even more important for production, a lack of vitamin A can stunt growth.

Vitamin A has a relatively short shelf life, and, as a result, dry feeds stored for extended periods of time may not contain adequate amounts of the vitamin.

After disease or stress, the immune system is at its weakest. When added to feed or water, a short course of vitamin A can help prevent further unnecessary illness, as without adequate supply of vitamin A, the bird is susceptible to a number of harmful pathogens.

Strengthening immunity  

Vitamin E is vital for growth and good egg production. It also contributes to a healthy immune system by increasing the activity of “microbe-eating” phagocytes, cells that ingest and destroy harmful bacteria. This promotes the healing of infected tissues and increases resistance to further infection.

As stores of this nutrient are depleted in the fight against any challenge to the immune system, including injections, it is extremely important that the animal’s vitamin E requirements are met.

Without enough vitamin E, especially after the immune system has been challenged, the bird is left susceptible to harmful bacteria and diseases including avian encephalomalacia. It is also associated with muscular dystrophy. This disease causes the degeneration of muscle fibres, affecting areas key for meat production including the breast and legs.

Aiding protein absorption
 
Unlike vitamins D, A and E, the B vitamins are water soluble. This means that they are not stored by the body and must be consumed regularly to provide a continuous supply. If a hen is not eating enough due to health problems or increased stress levels, supplementation with the B vitamins can help the animal get back on its feet.

Importance of vitamin supplements 

In light of difficult market conditions, rising raw ingredients prices and increasing competition, industrial poultry farming is more challenging than ever. Although micro- and macronutrient deficiency is traditionally fairly rare, the reduced feed intake during periods of stress or disease and the prevalence of pathogens in large flocks mean that an efficient nutritional strategy could be an effective solution for producers keen to safeguard production.

For the chicks and hens alike, D3, E and B complex vitamins contribute to a healthy immune system, as well as increasing energy levels and appetite after a period of stress. Vitamin supplementation is a good strategy for all hens, but is particularly important to boost the defenses of birds whose immune systems have been challenged by disease or even by vaccination. In addition, these micronutrients are essential for energy synthesis, increasing vitality of weak birds.