To avoid any doubt over how chickens should be handled once they are heavy enough to be sent for processing, it is worth reviewing the control points that have been developed for pre-slaughter and processing operations to ensure that these are carried out in the most humanitarian way possible.
The broiler industry is governed by a number of regulations as far as animal welfare is concerned. In the 1960s, the U.K.'s Brambell Committee established Five Freedoms to safeguard welfare during the various stages of production and processing, and its report was later built upon by the Farm Animal Welfare Council.
So what are the Five Freedoms?
- Freedom from hunger and thirst
- Freedom from discomfort
- Freedom from pain, injury or disease
- Freedom to express normal behavior
- Freedom from fear and distress
Ensuring that birds are treated optimally and kept in the best possible condition will improve the marketability of the final product.
Keeping stress to a minimum during handling will result in less carcass damage, and bruising and fractures, for example, will be minimized. Reducing stress can also lower the incidence of pale, soft and exudative (PSE) meat, and the incidence of blood in the wing tip.
To ensure high welfare levels, close attention needs to be paid to the following areas pre-slaughter.
Feed withdrawal should start 8-12 hours prior to slaughter.
It is worth remembering that if birds are given a long feed withdrawal, they will become dehydrated and so more resistant to the flow of electricity during stunning, and this can impact their welfare. A long feed withdrawal can also result in reduced muscle glycogen, so increasing the pH of meat.
Fear and stress
The careless treatment of birds during capture, unloading and storage raises stress levels and, should this happen over a long period, particularly in cold weather, there will be a loss of glycogen, which can lead to dark, firm and dry (DFD) meat.
In warmer weather, birds may experience heat stress pre-slaughter, and this ran result in hypothermia and lead to PSE. The rapid transformation of muscle glycogen to lactic acid is favored, and the final pH level is reached prior to carcass chilling, so aiding the denaturing of protein.
When catching birds, they should be approached from their blind spot - the tail area, and their wings should be held to prevent flapping. This is the best method for catching chickens as it minimizes bruising and physical trauma, which may result in the bird being rejected later on. Taking extra care during catching operations can result in more meat being sent to market.
The condition of cages for holding and transporting birds is also an important consideration. A split or broken cage risks injuring birds, so reducing welfare.
There are several issues that can affect bird welfare during transport. They include:
- Death due to heat stress
- Metabolic losses
- Psychological stress
- Skin lesions
Should transport time be prolonged, then the following may occur:
- An increase in breast lesions
- A reduction in hepatic glycogen
- A decrease in blood sugar levels
- The slow onset of rigor mortis
A number of actions can be taken to improve bird welfare at this stage of operations, including ensuring that no birds that have been harmed are transported; thoroughly training workers in chicken handling and making sure that they perform their tasks with great care; and, in hot climates, birds could be dampened. Doing this will not only refresh them, but also reduce the risk of hypothermia and the likelihood of PSE. It will also increase their meat's water holding capacity. In addition, dampening the birds aids bleeding, as blood vessels remain in their normal state.
Storage at the processing plant
The storage area should have proper air conditioning. There should be fans, extractors and misters in sufficient quantities, and they must be properly positioned so that heat removal is as efficient as possible.
To keep birds comfortable, temperatures should be 22-26C and relative humidity should be around 65 percent.
These facilities must have low light levels (15 lux) so that birds stay calm. Additionally, the area should be quiet, as noise will disturb the birds. Recommended waiting time is approximately two hours.
The number of birds per cage should reflect the weight of the chickens and the climatic conditions. This will help to prevent heat stress due to overfilling.
Unloading in the storage area
The area should be big enough to easily move the cages and to keep them horizontal while they are being handled, allowing them to be moved with care and not dropped, as this would hurt the birds.
Hanging on the overhead conveyor
This area must be also be kept darkened and only blue, red or green light used so that the birds always remain as calm as possible.
Birds should be carefully removed from cages and gripped with only three fingers. The thumb should be pressed against the thigh joint while the index and middle finger should hold the leg. Handling birds in this way will avoid applying any pressure on the lower part of the thigh and so avoiding bruising and reddening.
Additionally, birds should be hung on the shackles with care using a downwards motion until they are firmly in place. Should the birds' legs be too thick to reach the very bottom of the shackles, they should not be forced, or the birds will experience pain. Both legs should be level in the shackles. The breast comforter should then be in constant contact with the birds, as this gentle contact will help to keep them calm.
As the hanging areas is darkened, the fear and stress associated with being hung upside down is decreased. This is a strange position for birds to find themselves in, and by keeping them calm they will flap less and their wings will experience less damage.
Passage from the hanging area to the entrance of the stunner must meet various specifications to prevent bird welfare being compromised. Among them are that the trajectory of the overhead conveyor should be as straight as possible, as any curves or bends will disturb the birds and result in stress. This journey should be between 20-30 seconds only, to reduce the accumulation of blood in the wings as a result of gravity.
Birds should be prevented from flapping their wings. Flapping will result in a greater supply of blood to deliver oxygen and lead to its accumulation.
Paying attention to the above will affect the quality of chickens, as once they have been plucked, the accumulation of blood may be seen at the joint of the humerus and the ulna and radius. Additionally, there may be bruising and the wing tips will be red.
From a welfare perspective, the following need to be monitored:
- Pre-shock problems must be prevented, and these can occur when birds leave the water bath still conscious;
- The possibility of birds feeling pain during bleeding must be minimized;
- Stress during bleeding must be kept to a minimum to prevent injuries;
- Birds must be kept in relaxed to facilitate bleeding.
Those areas that need to be monitored to respect animal welfare include:
- Birds must be unconscious when the blood vessels are cut;
- Care must be taken not to cut the windpipe. If this happens, birds will not breathe properly and die from asphyxiation. Should this occur, on leaving the plucker, the carcasses will have a reddish appearance;
- A similar situation can occur should the cut be too deep and sever the nerves of the spine.
Following the above recommendations should respect animal welfare during pre-slaughter and processing. The result for the processor will not only be Grade A quality meat, which has greater customer acceptance, but also the satisfaction of knowing that birds have been treated well.