Category Archives: chicken

Blackhead disease (histomoniasis)

Blackhead disease (histomoniasis) is an important poultry disease that affects turkeys, chickens, and game birds such as partridges, pheasants, and quail. The disease is caused by the protozoa Histomonas meleagridis, tiny, single-celled organisms that are spread to the bird by the roundworm Heterakis gallinarum.

Lifecycle and Signs of Disease

The lifecycle of the protozoa H. meleagridis is complex:

  • The protozoa multiply in an infected bird’s cecum, a part of its digestive tract;
  • They move to the bird’s intestines where the roundworm H. gallinarum lives;
  • The roundworm eats the protozoa;
  • The roundworm’s eggs become infected with the protozoa;
  • The bird sheds the protozoal-infected roundworm eggs in its droppings.

Healthy birds become infected when they eat food, invertebrates (such as earthworms), or bird droppings that are contaminated with the protozoa. Direct bird-to-bird transmission can also occur within a flock. Because chickens, partridges, and pheasants commonly have the roundworm in their intestines, they often are the source of the protozoal infection for other birds.

Birds with blackhead disease are usually listless and have drooping wings, unkempt feathers, and yellow droppings. Typically, the cecum and liver of an infected bird will become inflamed and develop ulcers. Young birds become sick quickly and usually die within a few days after signs appear. The disease develops more slowly in older birds and they often become emaciated and may eventually die.

Turkeys are highly susceptible to blackhead disease. Once a turkey flock has been infected, 70 to 100% of the birds may die. In one survey, U.S. turkey industry professionals reported at least 50 outbreaks of the disease each year since 2009.1 Blackhead disease is less severe in chickens but can lead to poor health and reduced egg production



Curled toe paralysis

Curly Toe Paralysis

Other Names: Hypovitaminosis B2, Riboflavin Deficiency

Curly toe paralysis is caused by deficiency of riboflavin (vitamin B2) in young chicks. It is one of the most characteristic signs associated with the vitamin deficiency, resulting in the curling of the chick’s toes. The condition is nervous system related due to peripheral nerve damage, as a result of degeneration of the sciatic nerves (the nerves along the back of the chick’s leg to the foot). The damage can be reversed if treated quickly, however in longstanding cases where treatment is delayed the condition will become permanent.

Curly toe paralysis occurs in chicks fed outdated or improperly stored starter feed, or who are bred from parents with a riboflavin-deficient diet. Chicks that are fed a riboflavin-deficient diet will begin to show signs at about 8 to 14 days following hatch. They will slowly develop progressive symmetrical paresis starting with initial signs of reduced growth rate (despite a good appetite), weakness and sometimes diarrhea. Affected chicks soon become reluctant to move, followed by intermittent flexing and inward curling of toes. Without use of the legs, the muscles in the legs will start to atrophy and may eventually extend outward out from underneath the body of the chick.

During advanced stages of this condition, chicks are seen more frequently resting on their hocks, trying to walk as little as possible. It is at this later stage that chicks are at high risk of death from starvation, due to inability to reach food or water sources, or from getting trampled on by other chicks. The condition is still treatable however, as the chick’s peripheral nerves are able to rapidly regenerate once riboflavin levels are restored.

Nutritional Riboflavin Requirements

Nutritional riboflavin requirements for chickens fluctuate depending on genetics, stage of growth, environmental conditions, level of activity, health status, and other dietary components and synthesis. Riboflavin requirements are highest for newly hatched chicks and for chickens used for breeding. The NRC (1994) recommends that poultry species require between riboflavin at 1.8 – 4 mg/kg (0.45 – 1.8 mg/lb) of diet. However, more recently conducted research studies have found that the NRC’s recommendation is not sufficient for modern breeds of chickens, breeders, or growing chicks. All chickens should receive a diet with a minimum riboflavin content of 4.4 mg/kg (2.0 mg/lb), however the recommended riboflavin levels based on research conducted by DSM Nutrition is as follows:

Age/Life Stage mg/kg
Newly Hatched Chicks (0 – 10 wks) 6 to 7
Young & Growing (10 – 20 wks) 5 to 6
Laying hens (Actively laying eggs) 5 to 7
Breeders (20 wks & older)* 10 to 12
Broiler/’Meat’ Breed Chicks (0-18 wks) 6 to 8
Broiler/’Meat’ Breeds* (19 wks & older) 12 to 16

Dietary Food Sources of Riboflavin

Riboflavin is one of the vitamins most likely to be deficient in poultry feeds. Only a few feed ingredients that are used in poultry feeds that contain enough riboflavin to contribute to the requirements for growth and reproduction. Fermentation significantly increases the proportions of riboflavin present in the free form.

Clinical Signs

Toes curled inward like a fist (both when walking and resting) Weakness

Normal appetite

Diarrhea

Rough and dry skin

Diagnosis Treatment

Supportive care

Isolate the bird from the flock and place in a safe, comfortable, warm location (your own chick “intensive care unit”) with easy access to water and food

Vitamin B2 (Riboflavin)

Administered IM (1-3 mg/kg q7d) or orally (1-2 mg/kg q24h)

Feed management

Replace current feed with a new bag of quality chick starter feed.

Corrective shoe

Splinting the toes at the first sign of deviation. Involves taping the affected toes into a normal position for 2-3 days. This can be accomplished by making a corrective shoe, constructed from a piece of firm material such as thin cardboard or radiographic film. The shoe should be made to properly fit the foot of the affected individual with a notch in the shoe into which each toenail is placed in the shoe and each digit is taped into a normal position using very thin strips of masking tape. Should be monitored closely as deformities can be caused by leaving bandages or splints on too long.

Prevention

Ensure any adult chickens intended for breeding are receiving enough riboflavin in their diet (10-16 mg/kg).

Feed newly hatched chicks a fresh bag of starter chicken feed (not feed that has been stored for longer than 2 months), with additional riboflavin food sources during the two weeks of life.

During warm weather, provide supplemental sources of riboflavin.

Store feed in a sealed plastic container located away from direct sunlight.


Perosis disease

 Perosis is a nutritional deficiency that can cause swollen, twisted, broken, or bowed legs, or loss of color in feathers, the comb, or the roof of the mouth. Thankfully, nutritional deficiencies can be avoided by making sure your flock has free-choice access to complete, nutritionally-balanced feed. Don’t just feed them scratch or kitchen scraps; that can cause problems for them later on! Read on to find out more:


Perosis Also called
Slipped tendon, chondrodystrophy

Prevalence
Uncommon in layers, common in heavy, fast growing chicken breeds used for meat production.

Signs
General signs
Swollen hocks, one or both legs twisted to side, appearance of broken or bowed leg/s. In some cases (caused by niacin deficiency) the Achilles’ tendon may slip out of place and leg may be held at an odd angle, and the chicken may also have loose droppings. With folic acid deficiency, there may be brittle feathers, depigmentation of feathers, pale mucous membranes in the mouth, and pale comb. With biotin and pyroxidine deficiencies, the chicken may display dermatitis on the legs and feet.

Cardinal or diagnostic signs
Thickened bones in legs and wings on necropsy

Cause/s
Nutritional deficiency of choline, manganese, and/or B vitamins (such as niacin, biotin, and folic acid).

Communicability
Not communicable, but many members of a flock may share this problem if they’re on the same deficient feed.

Communicability to humans
No.

Incubation period
None, but as a deficiency, it takes some time to develop. In chicks of fast-growing meat breeds, may start around 10 days of age.

Latent
No

Endemic
No

Home treatment and/or prevention
Prevention: Provide a good, fresh, nutritionally balanced feed for your flock. Don’t make the mistake of offering something like scratch only, or kitchen scraps only.

Treatment: Supplement with bholine, B vitamins, and manganese.

Veterinary care
A veterinarian can diagnose this problem and suggest good supplements.

Recovery
Treatment will not correct damage, but will prevent the problem from getting worse or developing in other birds.

Other conditions, illnesses and/or diseases with similar signs:
Early stages may be mistaken for white muscle disease (nutritional muscular dystrophy), big hock disease (infectious synovitis), spraddle leg, broken limbs, or other illnesses causing leg problems



Perosis disease

 Perosis is a nutritional deficiency that can cause swollen, twisted, broken, or bowed legs, or loss of color in feathers, the comb, or the roof of the mouth. Thankfully, nutritional deficiencies can be avoided by making sure your flock has free-choice access to complete, nutritionally-balanced feed. Don’t just feed them scratch or kitchen scraps; that can cause problems for them later on! Read on to find out more:


Perosis Also called
Slipped tendon, chondrodystrophy

Prevalence
Uncommon in layers, common in heavy, fast growing chicken breeds used for meat production.

Signs
General signs
Swollen hocks, one or both legs twisted to side, appearance of broken or bowed leg/s. In some cases (caused by niacin deficiency) the Achilles’ tendon may slip out of place and leg may be held at an odd angle, and the chicken may also have loose droppings. With folic acid deficiency, there may be brittle feathers, depigmentation of feathers, pale mucous membranes in the mouth, and pale comb. With biotin and pyroxidine deficiencies, the chicken may display dermatitis on the legs and feet.

Cardinal or diagnostic signs
Thickened bones in legs and wings on necropsy

Cause/s
Nutritional deficiency of choline, manganese, and/or B vitamins (such as niacin, biotin, and folic acid).

Communicability
Not communicable, but many members of a flock may share this problem if they’re on the same deficient feed.

Communicability to humans
No.

Incubation period
None, but as a deficiency, it takes some time to develop. In chicks of fast-growing meat breeds, may start around 10 days of age.

Latent
No

Endemic
No

Home treatment and/or prevention
Prevention: Provide a good, fresh, nutritionally balanced feed for your flock. Don’t make the mistake of offering something like scratch only, or kitchen scraps only.

Treatment: Supplement with bholine, B vitamins, and manganese.

Veterinary care
A veterinarian can diagnose this problem and suggest good supplements.

Recovery
Treatment will not correct damage, but will prevent the problem from getting worse or developing in other birds.

Other conditions, illnesses and/or diseases with similar signs:
Early stages may be mistaken for white muscle disease (nutritional muscular dystrophy), big hock disease (infectious synovitis), spraddle leg, broken limbs, or other illnesses causing leg problems

Chicken illnesses with neurological symptoms

  • Avian Encephalomyelitis – Symptoms of this chicken illness loss of coordination, inability to stand, head shaking and other neurological issues
  • Botulism – Symptoms of this chicken illness can include paralysis of limbs and neck, tremors, torticollis
  • Egg Yolk Peritonitis – Symptoms of this chicken illness can include paralysis/partial paralysis
  • Encephalomalacia – Neurological symptoms of this chicken illness can include loss of balance, circling, head shaking or tremors, eventually convulsions, and paralysis
  • Lymphoid Leukosis – Neurological symptoms of this chicken illness can include leg paralysis and blindness
  • Marek’s Disease – Neurological symptoms of this chicken illness can include paralysis/partial paralysis (particularly of the legs), ataxis, blindness
  • Mycotoxicosis – Neurological symptoms of this chicken illness can include paralysis/partial paralysis, ataxis
  • Newcastle disease (either the domestic or the exotic variety) – Neurological symptoms of this chicken illness can include paralysis/partial paralysis of limbs, head twisting, walking in circles, walking backwards, clumsiness, tremors
  • Nutritional Myopathy – Symptoms of this chicken illness can include clumsiness/weakness due to muscle deterioration
  • Polyneuritis – Neurological symptoms of this chicken illness can include head shaking, tremors, convulsions, “star gazing” (paralysis of neck muscles)
  • Perosis – Symptoms of this chicken illness can include physical leg problems can be confused with neurological leg problems
  • Spraddle leg – Symptoms of this chicken illness can include physical leg weakness may be mistaken for neurological leg problems
  • VVD – Symptoms of this chicken illness can include physical leg deformity can be confused with neurological leg problems