One of the major changes includes an increase of over three fold in line speed.

Some of the new plants are designed to process up to 3,600 birds per hour on lines produced by equipment manufacturers such as Meyn in the Netherlands.

The plants are also now processing larger birds.

The increase in the speed of the lines and the growth in the weight of the birds being processed have resulted in a six fold rise in kilogram processed per hour.

The industry has also seen a large increase in the proportion of cut up and deboned meat that has helped year round sales, as well as substantial improvements in sanitation.

According to Shai Barbut professor at University of Guelph in a paper 'Developments in turkey meat harvesting technologies' published in World’s Poultry Science Journal, these advancements have been possible thanks to the knowledge gained in areas such as genetics, muscle biology, and post mortem processes.

Other areas of improvement include live bird handling including transportation, unloading and stunning, heat and mass transfer through scalding and chilling and computer science with the use of image analysis, in-line weighing and tracking.

Prof Barbut’s review, which includes a general summary of the steps involved in primary turkey processing, focuses on several principles that have been used to achieve greater efficiencies in mechanising the process.

The main focus areas where the industry has seen huge strides forward in recent years have been in the automating of unloading, stunning, chilling and mechanical filleting.

Prof Barbut says in his paper: “These areas show the importance of moving from a batch operation to a continuous line where speed, efficiency and traceability could be improved by mechanisation.

“Overall, integrating and automating the whole process is a challenge that must be met by both the processing plant personnel and equipment manufacturer, who should understand the whole farm to fork approach.”

The poultry processing equipment manufacturer Meyn says that turkey and broiler processing are in many ways similar, but the larger size and weight of the turkeys places much greater demands upon the system, requiring overall heavier duty engineering and build quality.

The large difference in weight and dimensions between turkey toms and hens requires a special approach when it comes to automatic processing.

Quick and exact adjustment between the two ranges is necessary in order to support the many flock changes that are common in most processing facilities.

Meyn said that its turkey evisceration equipment is fitted with hydraulic height adjustment with scales to facilitate the different ranges in size.

Meyn supports both 12 inch and 15 inch shackle pitches for all equipment involved. In case live weights over 15 kg are to be processed, Meyn strongly recommends that a 15 inch shackle pitch should be applied.

“The additional space benefits the in-feed of carcasses into the units of the evisceration machines,” said Meyn.

“The improvement in performance more than compensates for the reduction in capacity.”

The automated lines from Meyn are typical of the way line speeds have been increased. The Meyn line reaches speeds of 3,600 bph and once the bird is shackled on the line takes it through stunning, killing and bleeding, tail feather and wing feather pulling, scalding, plucking, rinsing, hock cutting and automatic rehanging on the evisceration line without the need for human intervention.

The evisceration and cutting is also carried out automatically with little or no intervention from people on the line, including tendon trimming and feet unloading, a head conveyor for horizontal processing, automatic evisceration through the Thor eviscerator, neck processing and through the automatic cropper wing and tail cutting and washing and through to the water chiller. Even the gizzards are cut and separated automatically.

The major human intervention on the line involves inspection and correcting any parts the automated process might miss.

Automation is also appearing on the cut up and deboning lines, speeding the process up for the delivery of further processed added value products and with the reduced human intervention increasing the biosecurity and hygiene on the line.

The use of automation in the harvesting and at the start of the processing line can also help to reduce stress on the birds and help to improve animal welfare.

Critical areas are in the loading and transportation of the birds from the farm to the processing plant, moving the birds into the stunning area whether it is by hanging them on a shackle to send them through an electric water bath stunner or through a controlled atmosphere stunner and at the point of slaughter and bleeding.

^{_{Video courtesy of the US National Turkey Federation}}

According to leading animal welfare expert Dr Temple Grandin, professor of animal science at Colorado State University, in a film made for the US National Turkey Federation, one of the advantages of using a conveyor and machine in loading the turkeys on to the truck to the slaughterhouse is that machines do not get tired, while people do.

Dr Grandin advises the producers to have close contact with the birds on the farm and walk through the birds as they are growing in the barns to ensure that they are used to people and remain calm. This helps when driving the birds onto conveyors to be loaded into crates on the lorries for transport.

However, Dr Grandin says: “Good equipment makes it easier to have good handling, but you also have to have good management.

“You have got to make sure they operate this equipment correctly.”

Dr Grandin says that if the birds are passed through a controlled atmosphere stunner at the slaughterhouse, the increasing mixture of CO2 that is used has to be raised gradually.

Whereas in a pig processing plant the mixture very quickly rises to 90 per cent CO2, in poultry plants it has to be slower to “avoid flapping and escape movements with the birds trying to get out of the chamber”.

The CO2 mixture anesthesises the birds, where in an electric water bath stunner, after the birds are shackled, they pass quickly on the line so that their heads are dipped into the water bath and an electric current renders then senseless by passing through the head to the shackle.

Any twitching or movement that is seen after the stunning is caused by a stimulation of the nervous system, Dr Grandin says.

However she added that it is important that immediately after stunning the birds should be bled.

“It’s absolutely essential that all birds are bled and dead before proceeding to the scalder and further processing,” says Dr Grandin.

Apart from welfare aspects, automated slaughtering and processing allows for better biosecurity and hygiene and allows for inspectors to be able to ensure good practice and to reduce the risk of contamination through human error.

While many processes down the line are still conducted manually, more and more are now carried out by machines and robots ensuring greater accuracy, better yields and better biosecurity.

June 2015