Vitamin D deficiency

Vitamin D3 and calcium work together in a bird's body: without vitamin D3 a bird cannot use the calcium in its food, even when there is enough of it. The consequences are soft and brittle bones, rickets in young birds and egg problems in females. The condition is most often seen in birds kept indoors without natural sunlight and in birds fed the wrong food.

Birds produce vitamin D3 with the help of the UVB rays in sunlight. Ordinary window glass lets through very little UVB, so a bird standing by a window does not benefit from them.

The most common causes:

• living indoors without direct sunlight or a suitable UVB lamp
• an all-seed diet – seeds are low in calcium and high in phosphorus
• the wrong calcium-to-phosphorus ratio (Ca:P) – for most birds the food should ideally contain about twice as much calcium as phosphorus
• young birds fed bread, milk, meat or unsuitable food
• females that lay eggs frequently and use up a lot of calcium in the process
• liver, kidney or digestive diseases

Fast-growing birds and egg-laying birds are particularly susceptible because their need for calcium is greatest. In some species, for example African grey parrots, low blood calcium more often shows up as trembling and seizures. In poultry, the deficiency is seen when chicks and laying hens are given feed that is not formulated for their age or are fed mainly kitchen scraps.

In young birds (rickets):

• bent, soft or deformed legs and wings
• a soft, pliable beak
• a crooked breastbone (keel)
• unsteady gait, sitting on the hocks, poor growth
• bone fractures without any major impact

In adult birds:

• eggs with thin, soft or no shells
• egg binding
• weakness, trembling and, with a severe calcium deficiency, seizures or falling off the perch
• bone fractures, lameness

General signs: loss of appetite, weight loss, lethargy, poorer and untidy plumage. These signs are also common in other diseases, so on their own they do not mean that the bird has a vitamin D deficiency.

• the bird has seizures, is trembling or falls off the perch
• a female is straining, sits fluffed up on the cage floor or cannot lay an egg
• a young bird has bent legs or cannot stand
• you suspect a broken bone
• the bird has not eaten for more than a day

Low blood calcium can be life-threatening, so such a bird should be examined the same day.

The vet will ask you about the bird's diet, light and age and examine it. An X-ray shows bone density, deformities and fractures, and a blood test shows the calcium level.

Treatment:

• calcium and vitamin D3 supplementation prescribed and dosed by the vet
• treatment of fractures and deformities
• in young birds: the right food and rest in a space where they cannot injure themselves
• changes to the diet and housing conditions

Important warning: do not give your bird vitamin D yourself. Too much vitamin D is toxic, causes calcium deposits in the kidneys and blood vessels and can kill the bird. It is also dangerous to combine several supplements, as many pellets and vitamin mixes already contain vitamin D3.

• Put the bird in a warm, quiet, dimly lit place, away from draughts.
• Remove high perches and put a soft towel on the bottom to reduce the risk of falls and fractures.
• Place food and water low down, within easy reach.
• Handle a bird with soft bones as little as possible.
• Do not force-feed it or pour water into its beak.

If you have found a wild baby bird with deformed legs or wings, contact a rescue centre or a vet. Wild birds are protected and are best off in the hands of experts.

• Light: let the bird spend time in the sun outdoors or behind mesh (not through glass), always with shade, water and supervision. A bird that lives indoors can have a UVB lamp designed for birds; replace it according to the manufacturer's instructions, as it weakens over time.
• Diet: good-quality pellets with vegetables instead of seeds alone.
• Calcium: a cuttlebone or mineral block in the cage, dark green vegetables such as kale and broccoli.
• For laying females: talk to your vet about diet and about how to reduce excessive egg laying.
• Never feed young birds bread and milk.

Vitamin D3 and calcium deficiency leads to soft bones, rickets and egg problems, but it is easy to prevent with a good diet and UVB light. Never give vitamin D on your own initiative – supplements are for the vet to decide. If there are seizures, fractures or egg problems, seek help immediately.