What could be causing the sudden death of your birds?

Ms Jesica Lakot, a broiler breeder in Bardege division, Gulu City, had just gone out of the poultry house in the morning when every bird was very ok but surprisingly learnt of an unusual mortality a few hours later.
A local veterinary officer who usually vaccinated the birds and helped her in formulating feeds, made haste to help her, although he found that everything about the birds was okay and there was no problem.

Strange disease
She said that the birds flapped their wings several times while stretching their necks, and jabbered around the pen before collapsing dead.

“Each of them collapsed on their sides on the floor, their eyes closed while their bodies were limp and sagging. They also showed no obvious signs of trauma: no blood, no injury, nothing stuck in her mouth or throat,” she explained.

According to her, their combs and wattles were cold and pale although their abdomens felt slightly warm.

But the deaths were so sudden and severe that it persisted until the third day when she invited an extension service provider who is also a veterinary specialist in town.

Investigation
When five birds were dissected to examine what could have occurred internally, they were surprised that each of them had bits of a blood clot in their hearts and lungs and the organs looked swollen and filled with fluid.

The condition was diagnosed to be sudden death syndrome. She was told that the heart and other internal organs of the broilers had failed to support their overgrowing body, hence a “system failure” which led to their sudden death.

Upon the advice issued to her by the extension service provider, Ms Lakot registered no additional deaths in the week that followed and all the chicken kept on doing their regular happy chicken things.

Causes of death
The Poultry Hub, an online poultry consultation platform, suggests several reasons to be responsible for the sudden death syndrome in broilers.

High levels of carbohydrates in the feeds. There’s this tendency by breeders to substitute bran with broken maize pellets. Feed texture can result in flip overs, farmers using pellets get this problem easily than those on mash.

Pellets are highly digestible and the release of carbohydrates from pellets is faster, compared to mash or tiny crumbles.

“The speedy release of fats leads to their accumulation in the bloodstream, which can lead to blockage and death,” says, Charles Ssekatawa a veterinary specialist.

Sudden death caused by a heart attack is a common condition among fast-growing broiler chickens. The birds die with a “short, terminal, wing-beating convulsion” and often flip on their back.

According to Ssekatawa, recent research suggests the heart attack is triggered by stress. “The chicken seem predisposed to heart attacks because of microscopic lesions in the muscle of their hearts,” he says.

“The syndrome is also caused due to limited supply of oxygen to the birds, a situation where a farmer closes everywhere on the house thinking that he has cut off the wind to create warmth.”

In layers, chicken can die if a fully-formed egg gets stuck somewhere between their shell gland and vent, the egg is too big, there is an injury to the reproductive tract that blocks the egg or the chicken has hypocalcaemia (calcium deficiency).

Expert view
Ssekatawa says that whereas many farmers have ventured into poultry farming specifically to make money, some of the farming practises on the farms often end up doing more harm to the chicken, and the farmers end up incurring losses.

According to him, a farmer’s ignorance of the dos and don’ts in poultry management is the common cause of sudden death syndrome.

“The sudden death in broilers is, for example, caused by farmers themselves who tend to overfeed the birds and they overgrow in the body leaving their body organs not proportional. This happens when the body of the birds grow bigger than the internal organs,” he says.

“Farmers also leave the light throughout the night, which is not recommended, at least birds should be left to stay in darkness for about 2 to 3 hours to avoid overeating,” he says.

Farmers want their birds to grow faster and so they end up feeding them on brands with a lot of broken maize particles in them. This causes the birds to have a lot of fats that block the passage of the blood to the heart, he notes.

“There is no medication for this syndrome but farmers should take critical steps by learning to reduce exposure to light, provide supplements to the birds and mix the maize well to avoid broken particles in the food.

One such instance is the practice of rearing averagely 30 chicken in coups which are dark inside and cramped for space. Farmers, especially those practising in urban settings, see this as a means to save space.

The small space is often presumed to be enough for the brood but decreases every week, forcing a farmer to sell off adult chickens to create space for the hatchlings. This, however, also brings complication to the birds, he says.

How to stop chicks from dying
Every farmer desires 100 per cent survival of chicks once he or she has bought and put them in a brooding house.

Losses will, however, almost always occur, especially during the first two weeks of life.

A mortality of 1-5 per cent may be considered normal, but anything above 5 per cent is abnormal and requires immediate intervention to stop further losses. Indeed some of the causes can actually wipe out the entire flock. Some of the common causes of mortality in brooding chicks include:
Genetic factors
There are many lethal gene mutations in birds, most of which cause death during the incubation period. A few, such as congenital loco and congenital tremors will cause death of chicks within a week of hatching.

To prevent this, farmers are advised to purchase day old chicks from reputable firms who select against such genes.

Management factors
The most common errors that famers commit include: High brooding temperatures. These result into two major problems, namely:

Dehydration
The body of young chicks comprises of about 70 per cent water. If temperatures remain continuously high, it results in loss of water from the body leading to dehydration. A water loss of about 10 per cent will cause death due to circulatory failure.

Pasting
This is when high temperature in the brooder house causes pasting or sticking of faeces around the vent leading to blockage and ultimately death of chicks.

Low brooding temperature cause chilling and pneumonia which kills chicks in high numbers. Dead chicks on post mortem show pale to blue lungs in colour.

Low brooding temperature makes the chicks to huddle together to keep warm and maintain body temperature. This further leads to smothering and death.

To prevent the effects of temperatures, a farmer should adjust the brooding room temperature 24 hours before putting the chicks in the brooding room and during the brooding period.

A farmer should also try to maintain the normal recommended temperature throughout the brooding period and evenly in the brooding areas.

Feeds
Feed poisoning such as fungal (mould) contamination or feed contaminated by toxic substances especially tannin found in saw dust and excess salt in water as well as toxic gases (Ammonia, carbon monoxide and carbon dioxide).

This should be avoided through use of proper feeding and use of clean water as well as proper litter management with regular mixing and removal to avoid accumulation of toxic gases in the brooder room. Adequate ventilation in the house is also very important.