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My interest in vitamin deficiencies in poultry began when my hen, Bartok, developed wry neck. Since then, I’ve been fascinated by how vitamin deficiencies affect birds and how they can be prevented and treated.

I believe that understanding how a vitamin works also leads to a deeper understanding of the diseases caused by its deficiency. After seeing an Instagram user talk about the importance of vitamin A for chickens, I became curious and wanted to learn more.

What Is Vitamin A and What Does It Do?

Vitamin A is one of the most important vitamins in the body. It is a fat-soluble vitamin that is primarily stored in the liver.

Its main role is to maintain healthy epithelial cells. These cells make up the skin and line the mucous membranes of the digestive, reproductive, and respiratory systems.

In other words, this essential vitamin helps keep the following healthy:

  • Mucous membranes

  • Skin

  • Vision

  • A strong and properly functioning immune system

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vitamin a brist höns

Symptoms of Vitamin A Deficiency in Poultry

Symptoms in adult birds:

  • Ruffled feathers

  • Weight loss and weakness

  • Reduced egg production

  • Lower hatchability

  • Small ovarian follicles, some with hemorrhaging

  • Milky, cheese-like discharge from the eyes and nostrils

  • Xerophthalmia (dry eyes)

If a laying hen is deficient in vitamin A, her chicks may also be born deficient. Depending on the amount of vitamin A stored in the hen’s liver, clinical signs can appear within the first 7 days after hatching.

Symptoms of Vitamin A Deficiency in Chicks:

  • Anorexia (loss of appetite)

  • Stunted growth

  • Loss of the yellow pigmentation in the shanks and beak

  • Pale comb and wattles

  • Chicks usually die before discharge from the eyes and nostrils becomes apparent

Foods Rich in Vitamin A

  • Kale

  • Pumpkin

  • Broccoli

  • Cantaloupe

My Thoughts

When reading about the effects of vitamin A deficiency, I can’t help but wonder how often it is mistaken for a respiratory illness. Vitamin A plays such an important role in maintaining the mucous membranes throughout a bird’s body, including those of the respiratory tract.

It also makes me wonder what other health problems these birds may develop if those protective tissues are no longer functioning as they should.

For that reason, I believe that whenever a bird is ill—regardless of the underlying condition—it is wise to include a high-quality multivitamin as part of its supportive care.

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