Process Control: 30 Specific Aspects to Evaluate from Pre-Slaughter to Slaughter

Process control focuses attention on the details and/ or micro-details that affect the quality and yield of the chickens processed daily. Process control is a managerial concept used by Toyota.

• The purpose of this article is to relate the most important aspects in each of these stages, in order to keep all the variables that govern them under control.
• Those who carry out this activity must develop the ability to visualize special situations, which should be kept in mind in the mental map of each operation and, when detected, should go directly to the point.

PRE-SLAUGHTER

Caged by the legs

Cages are part of the enclosures. The workers take the chickens by the legs, walk a little, and place them perpendicularly into the cages, taking two precautions:

• No part of the body touches the perimeter area where the lid is held.
• The place where they are placed in the cage is unoccupied.

Collectors catch the birds and walk with them, keeping their arms straight and without moving them, a distance greater than 20 meters on some occasions, to where the trucks are parked. The cages are next to the platform, which, once weighed, are loaded: manually and/or automatically onto the trucks.

Truck loading

If the cages are filled inside the sheds, once the loading is completed, they are moved manually and/or automatically.

• The stacks are connected to each other, like train cars pulled by a winch operated by remote control, leaving them near a reversible conveyor that lifts them onto the platform, on this reversible conveyor that lifts them onto the platform.
• In that place there are two groups of two operators, who place the stacks on special carts until reaching the height of 8 or 9 cages. Once completed, they are taken to the site next to the cabin where their organization begins.

Transport to the plant

In hot climates, some companies wet the chickens to cool them down at the farms.

• Once this activity is finished, the vehicles must depart immediately for the processing plant, to dissipate the evaporative heat that gradually increases.
• The manufacturers of trucks intended for this daily task offer platforms with all the best possible technologies so that the chickens remain within the comfort zone, regardless of environmental conditions that reach extreme levels.

Reference Parameters:

• Hot climates: 0.05% up to 0.10% of the total processed chickens. Example: 100,000 birds.
  • Dead chickens – DOA-, between 50 and 100 animals.
• Cold climates: 0.05%. Example: Process 100,000 chickens/day.
  • DOA: Maximum 50 chickens

JOURNEY

It is very important that the operators of these trucks remember that they are transporting a live, fragile load. Therefore, they must strictly comply with the rules established by the companies that own the chickens:

• Reduce speed on curves so that the action of centrifugal force is reduced, preventing the wings from hitting the inner walls of the crates.
• Speed bumps to reduce speed so that, when the vehicle passes over them, the platform rises as little as possible. In this way, the blows the animals receive on their backs are also reduced.

Arrival at the plant

Warm climate, after weighing, the trucks go to a washing station similar to those that exist on the farms.

• Depending on the size of the vehicles and the load, the time ranges between 30 seconds and 1 minute.
• Subsequently, they are moved to the waiting area where there must be adequate and effective infrastructure to extract evaporative heat.
• The monitoring of temperatures and relative humidity – RH – in this area is of utmost importance, so that the birds remain calm while waiting for their turn to be processed.
• In the market, sophisticated systems are available that allow the maintenance of the control parameters for these variables: 22ºC to 26ºC – RH: 65%. Each company sets these values.

PROCESSING

Live chicken hanging area

The birds arrive in this area in cages or in bulk; during this transfer, the animals remain inside their containers. For this purpose, a grid is placed to prevent the chickens from leaving the crates.

• In this way, no time is lost collecting the birds that walk on the floor of this section.

The live chicken hanging station must have, among other ergonomic aspects, the following:

• Two types of lights:
  • White which is used when the plant is not operating and/or during cleaning.
  • Blue when birds are being processed.
• Currently, double-filament bulbs are available, which facilitate their operation.
• Adequate air renewal received by the operators on the upper back and neck, preventing the dust from the birds’ feathers and skin from reaching their faces and obstructing their vision.
• When handling the chickens, removing them from the cages or from where they are in bulk, the workers hang the animals on the hooks forming an angle of approximately 45 degrees, a condition known as Normal Working Distance.
• This detail allows the staff to perform their work with minimal fatigue, increasing their productivity, measured in chickens/hour-worker, achieving up to 1,800 birds/hour-operator.
• This approach of the birds to the hooks represents a 1-hour break during the shift.
• The metal guide behind the hooks must be in permanent contact with them. In this way, the staff always has the hooks at the same distance.
• The hooks must not be broken or bent
• The hooks must be complete and connected to each other, in order to ensure the same distance in each of the operations carried out.
• All hooks must be filled.
• The chickens’ legs must reach the bottom of the hooks gently, avoiding damage or fractures to the legs.
• Depending on the type of hook, these can be modified to be expandable along the path the legs travel.
• The movement of the trolleys – wheels – must be carried out smoothly, without jolts. Under these conditions, the tranquility that the birds must have until reaching the stunner is not disturbed.
• The time for the last section from the hanger to the stunner entrance should range between 20 and 30 seconds, preventing blood from accumulating in the wings. Additionally, it is covered with a type of tunnel made of plastic canvas.
• The breast massager: It must be rigidly installed, allowing for horizontal and/or vertical adjustment according to the average weight of the animals.

Objective; Once the animals are placed on the hooks and released, they should not flap their wings, because the breast immediately comes into contact with this surface, which may be flat or circular. If this special condition is not met and the chickens flap their wings, more blood begins to accumulate in the wings. These extra amounts of blood affect the Grade A quality of the wings.

Important aspect: As far as circumstances allow, the route between hanging and entry into the stunner should have the fewest possible turns or changes of direction, in order not to disturb the calm state that the animals must maintain before entering the stunner cabinet.

Stunner

The critical points to be continuously checked so that the adjustments of this equipment are made according to the average live weight, sex, etc. are as follows:

• Electrical: Frequency, waveform type, voltage, amperage
• Time inside the tank: 10 to 12 seconds
• Tank height: the water level must be 3 centimeters below where the neck connects with the breast. This detail ensures that the water will never touch the breast, which is made up of two pectoral muscles that function antagonistically: Hinge type.
• Since the current consists of impulses and contractions, it promotes the rupture of blood vessels, resulting in hemorrhages and fractures of the fragile bones that make up the thorax.
• Pre-shock: the entry of the chickens into the tank must be unobstructed, as occurs in scalders.
• The water level in the tank must always remain at the initial height. Some plants have established that the chickens’ heads must be separated by approximately 2.5 centimeters from the perforated sheet through which the current is distributed.

Slaughter and bleeding

• In practical terms, a good stunning is confirmed when the chickens leave the stunner tank initially vibrating – tonic phase – and then completely relax – clonic phase –.
• In this calm condition, they must enter the guides of the automatic slaughter machines – killer –. This time ranges between 10 and 12 seconds, during which the animals fully recover their heart rate.