Poultry production has become a big business throughout the world. It is a highly competitive industry and feed suppliers, producers, processors, manufacturers of equipment have all appreciated the economies of scale. By so doing, they have gone on to develop bigger and more automated systems of operation than ever before to supply an insatiable market. It is a value addition process which produces ready-made chicken for consumption.
Following the ban on the importation of poultry products by the Federal Government of Nigeria as policy measures to revive the economy and encourage the local poultry farmers, there has been an increase in the number of poultry processing plants in the country. However, due to inadequate processing facilities to meet the local demand, the price of processed chicken increased by over 75% and has since opened up investment opportunity in the value chain.
Industry experts indicate that about 90% of broiler production are slaughtered, processed and sold as frozen chicken, while the rest is sold live in the open market and slaughtered in various homes. About 50% of the broiler produced are processed in automated slaughtering plants and stored in cold rooms before distribution and sale
The objective of a centralized poultry processing plant of any scale of operation is to produce material at a price which customers can afford, as well as that which is hygienic, wholesome, attractive, marketable and with a realistic shelf life.
Birds should be taken off feed and water when they reach “slaughter time”. This allows their digestive tracts to empty and reduces the potential for contamination during processing. Handling and transfer of birds both on the farm and at the slaughterhouse can be stressful. Stress can have negative effects on the quality of the final meat product, and therefore efforts are constantly being made to improve the pre-slaughter processes.
Stunning and slaughtering
After the birds have been transferred to the moving shackles, they are usually stunned by running their heads through a water bath that conducts an electric current. Stunning produces unconsciousness, but it does not kill the birds. The birds are slaughtered either by hand or by a mechanical rotary knife that cuts the jugular veins and the carotid arteries at the neck. Any birds not slaughtered by the machine are quickly killed by a person with a knife assigned to the bleed area. The birds are permitted to bleed for a fixed amount of time, depending on size and species (1 to 2 minutes for broilers). Any bird that is not properly bled will be noticeably redder after feather removal.
Following bleeding, the birds go through scalding tanks. These tanks contain hot water that softens the skin so that the feathers can be easily removed. The temperature of the water is carefully controlled. If retention of the yellow skin colour is desired, a soft-scald is used (about 50 °C, or 122 °F). If a white bird is desired, a higher scald temperature is used, resulting in the removal of the yellow pellicle. Turkeys and spent hens (egg-laying birds that have finished their laying cycles) are generally run at higher temperatures of 59 to 60 °C.
The carcasses pass through the feather-picking machines, which are equipped with rubber “fingers” specifically designed to beat off the feathers. The carcasses are moved through a sequence of machines, each optimized for removing different sets of feathers. At this point, the carcasses are usually singed by passing through a flame that burns off any remaining feathers.
Removal of heads and legs
The heads of the birds go into a channel where they are pulled off mechanically; the legs of the birds are removed with a rotary knife either at the hock or slightly below it. The carcasses drop off the shackle and are rehung by their hock onto the eviscerating shackle line.
At this point, the preen or oil gland is removed from the tail and the vent is opened so that the viscera (internal organs) can be removed. Evisceration can be done either by hand (with knives) or by using complex, fully automated mechanical devices. Automated evisceration lines can operate at a rate of about 70 birds per minute.
Washing and Chilling
The inner part is washed in cold chlorinated water and chilled in cooled water. Several designs of chilling equipment in use include immersion chillers, static water chillers, spray chillers.
Carcasses may be prepared as whole birds or cut in different sizes depending on customer requirements. This may include cutting into halves, quarters, legs, thighs, wings, breasts, drumsticks or complete deboning. The products are packed to preserve the shelf life.