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Poultry Processing & Slaughter / Broilers & Layers
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Accumulation of blood leads to enlarged wing veins.
on June 16, 2015

Reducing redness, damaged carcasses during poultry processing

From capture to plucking, broilers must be handled with care to minimize the amount of damage to carcasses.

Broiler production and processing need to be carefully coordinated if growing demand for processed broiler meat is to be satisfied. Meeting this demand not only benefits the processor, but also the client and, in a world where the population continues to rise, improves the diet of the population as a whole.

To satisfy this growing demand, the large volume of condemned product from processing plants needs to be reduced.

Waste increases not only the cost per kilo of processed meat marketed, but also means more birds need to be processed and more hours worked to ensure supply.

Causes, prevention of reddened wings

Heat stress, leading to the accumulation of blood in the wings, can be caused by several situations. Take, for example, the harvesting and caging of birds.

When cages are introduced into the house manually, workers can move quickly and make a lot of noise, disturbing the birds. Similarly, if cages are delivered by forklift truck, the driver may be under time pressure, and noise levels in the poultry house can similarly increase.

In addition, the increase in light when birds are harvested also has a negative impact on their behavior.

Birds become agitated and, to escape from what is disturbing them, will run and jump, often onto each other. This results in exertion of the wings and an increased supply of blood to supply oxygen to the wing muscles.

Within the broiler, 15 percent of blood is in the arteries, 5 percent is in the capillaries, 64 percent in the veins, and 16 percent in the organs. Oxygenated blood is pumped at great pressure through the arteries, which are rigid and so cannot expand.

On entering the tissue, their size diminishes, and arteries become arterioles. They then branch out into capillaries, supplying oxygen and nutrients to cells. As a result of this supply process, carbon dioxide is produced along with some residues, which enter into the capillary network.

These capillaries drain the deoxygenated blood to the venules, which eventually connect to the bigger veins. These blood vessels, despite having the same number of layers as the arteries, are not as thick, and consequently are more flexible. The extra volume of blood that is pumped to the wings when flapping accumulates in the network of vessels, and if environmental conditions exceed the birds’ comfort range, the blood vessels move toward the surface of the skin to dissipate heat.

Redness of the thighs

Heat stress, noise and excessive light, particularly in open houses when birds are harvested during the day, will lead to the accumulation of blood in the muscles. This is not the only reason, however, that blood accumulates in the muscles.

It is worth remembering that, if birds are kept in cages for long periods during transport to the processing plant, they will lie down, and lying down for long periods can have the same effect, resulting in the thighs taking on a reddened appearance.

Maintaining thigh quality, however, can be achieved via few simple steps:

  • In open poultry houses, special enclosures can be erected in those areas where the birds are to be harvested. These are made from a special material that blocks the passage of light but not the circulation of air.
  • Explain the importance to the catching team of keeping as quiet as possible while performing their duties.
  • Traditionally, forklift trucks have been run on fuel, but they are noisy. Some companies are now using electric forklifts, similar to those used in in the coolers and dispatch areas of processing plants, to keep noise to a minimum. 
  • Carefully plan transport to the processing plant and consider any time that broilers must wait at the plant before slaughter. No more than three hours should elapse between capture and slaughter, although there will be times when this period is longer. 
  • The waiting and hanging areas of the processing plant should be illuminated with only red, blue or green light and should be well ventilated. A comfortable atmosphere will result in the birds being more relaxed.
  • Hanging birds on the overhead conveyor should be performed with the utmost care and efficiency, so as not to exert pressure on thigh joints.

Causes of hemorrhaging, bruising

If broilers are caught by the legs, it should be remembered that flapping will occur. The sharp jolt that birds experience when they are caught by one leg can rupture the femoral blood vessels, and dislocate the femur.

Should dislocation occur, more blood vessels will break and even the abdominal air sac can be ruptured, and blood will accumulate there. Additionally, the tendon close to the gastrocnemius muscle can tear.

When collecting the birds and moving them into the cages, care should be taken that the birds’ wings do not flap against the drinkers and feeders, house doors and the cages themselves. 

If cages should be broken, birds may be wounded during transport from the farm to the processing plant due to the movement of the truck. If road surfaces are poor along the route, the risk of damage to birds increases. 

Should the hanging area not be darkened and lit only with appropriate lighting, and the staff in this area careless, birds will flap their wings which can not only result in damage, but also leads to the accumulation of blood in the wings. 

If when entering into the water bath, birds flap their wings intensely, hitting the walls of the cabinet and the entrance ramp, which may be damp and carrying electric current, hematomas may occur. This situation is known as pre-shock.

If stunning is not properly performed, during bleeding the birds will also flap their wings due to the intense pain, increasing the possibility of hematomas and hemorrhaging. 

If all stunning variables are not properly adjusted, the chicken’s most fragile bones, located in the thorax, may be broken. Consequently, the capillaries are ruptured, and blood accumulates around them, producing hemorrhages in the pectoral muscles.

Possible solutions

A number of easy measures can be taken to reduce these problems:

  • Capture birds by the body rather than the legs, keeping the wings close to the bird’s body to prevent flapping.
  • Only cages that are in good condition and that have doors should be used.
  • The waiting area should be properly equipped so that birds remain as calm as possible during handling. 
  • Any problems with the entrance to the stunning bath should be resolved. The entrance should resemble that of the scalder.
  • Draw up a table listing the correct voltage, amperage, and frequency to be used during stunning, depending on birds’ weight and sex. This should be displayed next to the stunner control panel.

Wing dislocation

Wing dislocation can be the result of applying too much pressure during plucking. But poorly performed plucking can also result in additional problems, such as the dislocation of the main wing bones. If the plucking equipment is properly adjusted, however, this problem does not occur.

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