8 key questions to understand vent cutting

1. What is vent cutting?

Vent cutting is a crucial step in poultry processing. After defeathering, it’s the first operation in the evisceration department, needed to get a ‘clean’ whole griller without guts. Vent cutting involves removing the cloaca aka vent (the common exit for the digestive, urinary, and reproductive tracts) from the bird. Vent cutting is about making a precise cut around the vent to release it without damaging the intestines. The vent should be cleaned, clamped, cut, drawn out complete with bursa fabricii and urethra and hung over the back of the product.
This operation must be performed with utmost precision and hygiene to ensure the best possible conditions for clean and efficient downstream processes. Vent cutting can be done manually, but in high speed primary processes, automation is required. A specialized machine, the vent cutter, is built to remove the cloaca precisely and hygienically with a near 100% success rate.

2. Why is it so tricky?

The vent cutter is the first machine in the evisceration line and therefore its performance determines largely the success of the total line. This initial step demands precision, consistency and highest attention to hygiene standards. If not, the domino effect will mean nearly fatal consequences to the entire product yield. If the first step isn’t of the highest quality, initial errors can’t be corrected anymore by the subsequent processing steps in the line without compromising the quality and safety of the product.
The biggest risk is accidentally damaging the intestines, which can release fecal matter onto the meat and equipment, leading to contamination and potential food safety issues. To avoid this, the cut must be precise and controlled.
In this context, it is important that the intestines are fairly empty to reduce the chance of fecal contamination of the meat and the equipment. When the intestines are full, there is a higher chance of rupture during vent cutting and evisceration. Therefore, feed withdrawal of around 8-12 hours for broilers prior to processing is essential.*

3. What are the exact maneuvers?

From manual cutting of the skin around the cloaca in a circular pattern with a knife, the mechanical process has evolved to automated drilling, combined with vacuum suction.
First, the positioning of the carcass is crucially important in ensuring that vents are cut consistently accurately. Each product should be guided carefully into the vent cutter and precisely positioned in one of the units. Here, the help of a hip lifter and a spreader bracket is useful.
Then the drill, in the form of a hollow pin, descends to drill out the vent. Achieving the right drilling depth to release the cloaca without damaging the intestines requires a delicate balance to prevent contamination and maintain product integrity. The latest generation vent cutters offer automatic control of the depth of the drill entering the carcass. It is dynamically adjustable per millimeter, allowing the drill to go precisely as deep or shallow as needed without touching the intestines. Human errors are excluded.

4. Why isn’t the cloaca simply cut off?

If the cloaca were simply cut off, the intestines would be left with an open end, creating a serious risk of soiling and contamination. Instead, it is carefully drilled out and positioned on the back of the carcass, remaining connected to the intestines and other viscera still inside. This ensures a controlled and hygienic removal of the cloaca and a proper downstream process. The next machine in the line, the opening machine, works around the positioned cloaca in the direction of the breast. Finally, the eviscerator extracts the entire viscera pack, including the edible giblets, intestines, and, at the bottom end, the cloaca. Only at this stage is the cloaca fully separated from the carcass.

5. How does vent cutting ensure hygiene?

As the first operation inside the carcass, vent cutting requires the highest hygiene measures to prevent exposing the meat to high microbial loads.
Vacuum is applied to the rectum to suck out feces from the end of the digestive tract, minimizing the risk of fecal contamination of the outside or inside of the product. Next, the vent is clamped and a circular rotating blade cuts off the bursa fabricii and urethra, leaving the kidneys and tail intact. The vent is drawn out (while the connection with the intestines still inside remains intact) and placed over the back of the product, a hygienic technique that prevents contamination. This positioning of the cloaca must be correct, so it can be processed efficiently downstream.
Every individual drill in the carousel is rinsed after each insertion and extraction by its own spray washer. In the carousel machine, the pitch between the shackles should be big enough, so products don’t touch each other.

Hygiene focused design helps keep the machine clean during operation. Even simple features such as sloped surfaces can help prevent water or debris accumulation on equipment. Avoiding blind spots also enables the machine to stay clean during operation and a water spray can be used to remove any material that falls on equipment.

6. Can vent cutting adapt to chicken sizes?

Traditionally, vent cutting relied heavily on the skills of the operator to set the machine in a way to perform the best possible cutting maneuvers with a ‘perfect average’ setting for all carcasses. However, advancements in technology, such as the introduction of intelligent vent cutters, have made the process more efficient and reliable, independent of human skills. Modern vent cutters are designed to handle large variations in flock weight and ensure precise cutting no matter the size or weight of the products, leaving behind the average settings. Pre-set flock settings allow the machine to adjust automatically. Even in-flock variations, with wider weight spreads, can be handled. The automated adjustments help maintain labor-free, consistent performance across different flock sizes.

7. Can vent cutting contribute to water savings?

Some systems, such as VC-i, include smart water management, where spray-cleaning of the drill units automatically stops when there is a longer sequence of empty shackles due to a production pause. This reduces unnecessary water use and lowers operational costs.

8. Can vent cutting performance be monitored?

Advanced vent cutting systems, such as VC-i, provide real-time performance tracking through dashboards, giving insights into machine health and efficiency. This allows for proactive maintenance, preventing breakdowns and ensuring continuous operation.

AI technology can be used to pick up incorrectly cut and hung cloacas as well as one-leggers. In this way, a vent cutter no longer requires a highly skilled operator to recognize and count the number of correctly positioned cloacas, which pass by incredibly fast. Instead, AI-based technology can give real-time insight into the machine’s performance and settings. This kind of automation is completely objective, unbiased and does not make mistakes when counting.


* source: "The Science of Meat and Poultry Processing" by Shai Barbut