Poultry Management Related Disease
Caged Layer Fatigue
Poultry Management Related Disease – Cage layer fatigue is a condition that is unique to hens that are in a high state of egg production, primarily caged layer hens. The cause of the condition is thought to be associated in an imbalance of minerals/electrolytes in the body.
Rickets and abnormal bones in adult birds is commonly present. In layers under thirty weeks of age, the cause is usually a temporary calcium deficiency when egg production reaches eighty percent or higher. If intake of calcium does not satisfy the need for egg production, the hen will remove calcium stored in the bones. Ultimately, osteoporosis develops, bones become soft and hens are subject to bone fractures. Crippled and unable to stand, the hen suffers from the caged fatigue symptoms.
Many hens show spontaneous recovery if removed from the cages and allowed to walk normally on the floor. This indicates that a lack of exercise may be a partial cause. Cage layer fatigue is more prevalent in single-hen cages than in multiple-hen cages. When two or more hens are caged together, they get more exercise because of competition for feed and water.
Supplementation of the diet with phosphate, calcium and vitamin D3 is usually helpful. Adding calcium to young birds by top-dressing the feed with twenty pounds of oyster shell or limestone per one thousand hens will often help the condition. In older hens, calcium deficiency is less likely than phosphorus or vitamin D3 deficiencies. Recommended treatment in these birds is to remove the hens from cages and top-dress feed with equivalent level of dicalcium phosphate. Adding a vitamin/electrolyte supplement to drinking water is recommended in any age bird suffering from this condition.
Flocks that do not respond to the above therapy should be submitted to a poultry disease diagnostic laboratory to determine the cause of the problems. Several diseases can cause symptoms similar to caged layer fatigue. Flock treatment for the condition can be prescribed after diagnosis is completed.
Fatty Liver Hemorrhagic Syndrome
Poultry Management Related Disease – Fatty liver syndrome is a condition that affects only hens. The basic cause is thought to be excessive dietary energy intake. Hereditary tendencies vary among various strains of egg production stock, but heredity is not the entire cause for this malady. Laying hens housed in cages are most often affected since they are less able to get sufficient exercise and dispose of the extra dietary energy.
Birds within a flock that are most often affected are the high producers. This indicates that physiological energy metabolism and production are closely associated with this condition. Mortality varies considerably among flocks but can become excessive in some cases. Lesions include accumulation of large amount of abdominal fat; enlarged, easily damaged liver and presence of blood clots that indicate that hemorrhages have occurred prior to death. Death usually is caused by a fatal internal hemorrhage originating in a portion of the liver. This hemorrhage is often caused as the hen is straining to lay her egg and the enlarged, friable liver is more vulnerable to injury. When a large blood vessel ruptures, sufficient blood is lost to cause death of the hen.
The primary treatment for this condition requires an alteration of the diet or amount of dietary energy consumed. Replacement of some of the corn in the diet with lower energy feedstuffs like wheat bran can provide a lower energy diet. If a complete layer ration is being fed, addition of vitamins can be of benefit. If grains are the primary feedstuff, it is suggested that the birds be switched to a complete layer diet. Control of body fat is the only successful remedy for this condition and is best accomplished by regulation and reduction of total energy intake.
Poultry Management Related Disease – Poultry Cannibalism is prevalent among chickens of all ages and can become a serious problem if not corrected early. The problem is most severe when birds are housed in close confinement. In most cases it is a vice that progresses from a minor stimulus and soon becomes a severe problem.
Many causes are thought to initiate the problem but it is not understood why it is uncontrollable in some cases but never becomes a problem in other situations. Cannibalism may start as toe picking in baby chicks; feather picking in growing birds; or head, tail and vent picking in older birds. The early symptoms of a cannibalism problem may be difficult to detect. It is necessary that the poultry man be on constant guard to detect any aggressive behavior and take necessary management changes before the problem progresses into a severe case of cannibalism.
Causes that can result in cannibalism include:
- High density of birds within a confined area,
- Brooding chicks at temperatures that are too warm,
- Small or weak chicks, especially those having oddly colored down or feathers,
- Exposing birds to light that is too intense or having a color that induces aggression,
- Restriction of feed or water intake,
- Feeding a diet with a deficiency of salt or sulfur-containing amino acids (protein),
- Allowing dead birds to remain exposed to the flock,
- Lack of or absence of properly designed nest boxes.
Regardless of the cause, some method of preventing this vice must be used. The most common procedure to reduce cannibalism is to debeak the birds. Birds grown in houses with very low light intensity may not require debeaking. Those grown in houses receiving normal daylight should be debeaked at the hatchery or within the first two weeks after hatching. This helps reduce the incidence of feather picking that often develops into a severe case of cannibalism.
A special method of hot debeaking has been developed for debeaking broiler chicks at one day of age. Rather than severing or cutting the beak, a hot blade is used to burn an area near the tip of the upper beak (egg tooth). The procedure is designed to leave a thin base to the tip of the upper beak. This makes it easier for the chick to eat without having a sensitive, raw beak. The tip of the upper beak gradually drops off without apparent injury to the chick, thus leaving a shortened upper beak and a normal lower mandible.
Reducing the mortality is a primary concern that responds well to adequate floor space. Birds should not be crowded but instead, provide sufficient room so that weaker birds can escape from those that are more aggressive. Reducing the amount of floor space usually results in increased mortality and reduced growth rate. Not only is there a monetary loss involving the cost of the chick, but the value of the feed, labor, and other items necessary to grow a chick until the time of death is a direct loss. There is also the lost profit that could have been earned if the dead birds had lived until market or egg production age.