Vitamins for chickens: are supplements a necessary part of a healthy poultry diet?

Vitamin A for chickens

(Sources: 3, 4, 5)

• Boosts the immune system
• Regenerates cells
• Helps bone development
• Keeps throat, eyelids and nostrils moist
• Helps deal with stressful situations such as cold weather and moulting
• Often deficient in poultry diets
• Blood spots in eggs can indicate deficiency.

Lack leads to...

(Sources: 4, 6, 7).

• Poor immune response
• Damage to eyes, nose and throat
• Respiratory infections, specifically infectious Coryza
• Can prove fatal quickly.

Found in...

• Dandelions: which also contain potassium, iron and calcium.
• Fish: particularly oily fish such as mackerel. Find a poultry fish recipe here.
• Eggs: making sure chickens have adequate Vitamin 'A' equally ensures their eggs are rich in it. More about eggs and chickens, here.
• Pumpkin: one of the best sources of beta-carotene, a powerful antioxidant which converts to vitamin A in the body. Click to see more about pumpkins, including a recipe.

Vitamin B complex

(Sources: 8, 9).

• Vitamins B6 and B12 are particularly important
• Both help absorb proteins; B12 also metabolises fat and carbohydrate
• Promote healthy growth
• Contribute particularly to healthy bones and feathers 
• Particularly critical for hens laying eggs for hatching
• Weight loss and convulsions indicate a lack of the 'B' vitamins.

Lack leads to...

(Sources: 8, 9, 10).

• Convulsions, wing flapping and falling over in chicks
• Reduced appetite 
• Feather loss
• In adults, shrinking of wattles, comb and oviduct
• Consequent decrease in egg production in laying hens, and...
• Poor success rates in hatching; embryos dying midway through incubation.

Found in...

• Sprouting seeds, particularly lentils and mung beans
• Sweet potatoes
• Bananas, which also contain high levels of potassium and iron
• Fermented feed
• Fish and meat.

Vitamin C for chickens

(Sources: 3, 9, 11).

• Supports the immune system, especially in cold weather
• Protects cells against damage – it's an antioxidant
• Contributes to healthy bone and feather growth
• Essential for certain enzymes to function
• Improves the way the chicken processes the food it eats, so makes normal feed more efficient – the chicken need to east less to sustain the same – or better – level of health
• Supports the production of hormones involved in resistance to general stress levels
• Some evidence of anti-inflammatory properties
• Produces better quality egg yolk.

Lack leads to...

(Sources: 3, 9, 11).

• Increased mortality due to poor immune system response and increase in toxins, especially at times of stress
• Cell breakdown and critical illness
• Increased likelihood of staphylococcal infections
• Susceptibility to critical illness in cold weather.

Found in...

• Some plants, especially nasturtiums and marigolds
• Berries and fruits, especially strawberries and watermelon
• Rose hips
• Vegetables, especially cabbage and broccoli
• Some herbs, particularly parsley
• Fermented foods.

Vitamin D complex

(Sources: 3, 9, 12)

• Enables the absorption of calcium and phosphorous
• Therefore helps sustain strong, healthy bones and egg shells
• Contributes to improving immune system response
• Has some anti-inflammatory properties
• When Vitamin D is not available in the diet, it is taken from the chicken's bones to create stronger egg shells.

Lack leads to...

(Sources: 3, 9, 12)

• Decreased egg production
• Small, thin or soft-shelled eggs
• Calcium spots on eggs
• Unsuccessful hatches from eggs of hens suffering deficiency
• Bent, malformed or soft beak, feet and keel bone
• Bowed legs (rickets)
• Stunted growth.

Found in...

• Known as "the sunshine vitamin" since sunlight is the best source of this vitamin for chickens (and for people!)
• It has to be outdoors – glass windows glass don't allow necessary penetration of ultraviolet rays
• Oily fish such as mackerel, tuna and salmon
• Egg yolks
• Mushrooms
• Supplements.

Vitamin E for chickens

(Sources: 3, 9, 13, 14, 15)

• An antioxidant which helps boost the immune system and acts to suppress free radicals
• Maintains healthy cell growth
• Protects against, but does not cure, diseases such as coccidiosis, e.coli and bronchitis
• Increases shell density
• Helps boost fertility in adult males and egg quality in females
• Increases hatch success levels
• A mother hen passes antibodies to chicks, giving immunity against infectious diseases.

Lack leads to...

(Sources: 3, 9, 13, 14, 15)

• Decreased fertility in both males and females
• Poor hatchability
• Wry neck in baby chicks
• Depleted immune system with increased likelihood of disease
• Degeneration of muscular and heart condition, leading to a poultry form of muscular dystrophy, also known as "nutritional myopathy" and "white muscle disease"
• Increased mortality.

Found in...

• Generally agreed that the amounts in a good quality feed are sufficient
• Sunflower seeds and sunflower oil are one of the best sources
• Nuts, in particular almonds, pine nuts and hazelnuts
• Pumpkins and squashes, especially the seeds.

Vitamin K for chickens

(Sources: 9, 16)

• Improves bone structure and flexibility
• Aids strong growth
• Ensures blood clotting times
• Improves hatchability of fertile eggs
• Particularly useful for older chickens.

Lack leads to...

(Sources: 9, 16)

• A poultry form of osteoporosis (thin bones) leading to increased fractures
• Thin blood with poor clotting times and increased risk of hemorrhage
• Increased risk of bruising and damage to internal organs
• Increased chick mortality at a late stage of incubation.

Found in...

• Leafy green vegetables such as lettuce, cabbage, spinach, brussels sprouts and broccoli
• Fresh garden peas
• Don't freeze these vegetables – it destroys vitamin K.
• Stinging nettles
• Fermented foods
• Parsley (flat-leafed).

Calcium

(Sources: 17, 18)

• Increases the strength and optimal quality of eggshells
• Found to reduce the number of cracked eggs from older hens
• The chicken embryo begins to add strength to bones by absorbing calcium from its shell while still in incubation
• Stengthens bones
• An excess of calcium can lead to damage to the kidneys, particularly in chickens under 18 weeks old.

Lack leads to...

(Sources: 17, 18)

• Weakened bones, as hens deficient in calcium will take it from their bones, which leads to...
• Increase in fractures
• Lameness
• Decreased egg laying
• Soft shelled eggs, which can result in egg peritonitis
• Poor or no hatchability from fertile eggs.

Found in...

• Crushed oyster shell – the best way to make sure your hens have enough calcium
• Eggshells can also be used, but may not contain enough calcium to meet hens' needs
• Feed freely: hens will take as much as they need and males will not take any
• Soft bones of canned oily fish such as mackerel and, in particular, salmon
• Green leafy vegetables such as broccoli, kale and Chinese cabbage
• Dairy products are high in calcium, but not digested well by poultry. Avoid them.

Iron

(Sources: 20, 21)

• Transports oxygen to cells to maintain general bodily and organ health
• Ensures egg quality
• Increased nutritional value of egg yolk
• Necessary for the healthy development of baby chicks

Lack leads to...

(Sources: 20, 21)

• Anaemia, indicated by a very pale comb and wattles
• Weight loss
• Inactivity, "droopiness", lack of interest
• Decrease in egg production
• Poor hatchability of fertile eggs
• Often caused by undetected mites who feed on chicken blood.

Found in...

• Too much iron is toxic for chickens, so unless your chicken has suffered an injury and has lost a lot of blood, do not offer any supplements which have a concentrated iron component
• Otherwise, a good quality feed should provide as much iron as chickens require
• Some unprocessed foods contain traces of iron and can be given, but infrequently. They include:
• Lentils
• Sprouted seeds
• Eggs.

Phosphorous

(Sources: 22, 23)

• Critical in the absorption of some vitamins and minerals, particularly calcium and Vitamin A
• Therefore essential for healthy bones and cell development
• For the same reason, ensures strong, high quality egg shells
• Increases protein quality of egg whites
• Improves egg yolk colour
• Enhances the immune system
• Supports healthy cell structure, improving general health and ability to withstand disease.

Lack leads to...

(Sources: 22, 23)

• Decrease in egg production
• Weak or soft-shelled eggs, more likely to break or lead to egg peritonitis
• Poor nutritional quality of eggs
• Weak, soft bones more likely to break
• More likely to succumb to stress and disease.

Found in...

• A good quality chicken feed should contain sufficient amounts of phosphorous
• Some additional sources are:
• Nuts
• Lentils
• Peas
• Celery
• Sardines.

Potassium

(Sources: 24, 25)

• Essential for eggshell thickness
• Critical to healthy development of baby chicks
• Required for healthy muscle development in all ages
• Supports healthy heart function
• Helps chickens deal with extreme heat stress.

Lack leads to...

(Sources: 24, 25)

• Reduced egg production
• Reduced shell thickness
• Poor development for chicks
• Increased potential for heart problems.

Found in...

• Pumpkins and pumpkin seeds
• Brussels sprouts
• Sweet potatoes
• Spinach
• Bananas.

Sodium

(Sources: 26, 

• Welfare standards relating to food are clear that "ensuring sodium content of feed is appropriate" is critical
• Chickens need a small amount of salt, but adding salt into their diet is toxic
• 0.2% is the recommended level; 0.4% is already toxic
• Stick with a good quality feed which will have enough salt as part of its balance
• This is one mineral chickens do not need more of!

Too much leads to...

• Increased thirst
• Difficulty walking
• Diarrhea
• Breathing difficulties
• Convulsions
• Death.

Found in...

• Processed foods. Always feed your chickens natural treats
• Do not add salt into your chickens' diet!