Mississippi State University
Poultry Science Department
Most commercial poultry houses utilize tunnel ventilation and evaporative cool cell pads to maintain flock performance and keep birds alive during periods of hot weather. Cool cell pads are valuable; however, it is the fans (and associated wind chill and airflow down the house) that are critical to success with tunnel ventilation. Evaporative cooling pads are often used because of their cooling efficiency, despite the fact they can consume large amounts of water. Foggers were once used as auxiliaries to cool cell systems even though their cooling potential was limited. However, foggers are rarely used today because they further increase humidity level in the chicken house, making it more difficult to provide effective bird cooling. Consequently, large numbers of heat losses can occur when foggers are utilized in combination with cool cells, even though air temperature in the house may only be in the low 80s. However, it’s not heat alone that kills chickens during hot weather. It’s the combination of heat and humidity.
An alternative to cool cells is sprinkling birds on a specific schedule with large drops of water. Cattle and hogs are often cooled in hot weather by sprinkling with water. And years ago, poultry producers often hosed down large birds with garden hoses to keep them alive during extremely hot periods. Low-pressure sprinkler systems do not work by cooling the house temperature, but rather by letting house temperature rise and humidity level decrease and then cooling individual chickens by sprinkling them with water. The initial inclination may be to think that sprinkling water in a chicken house will wet the floor and ruin litter conditions, but this is not the case. When managed properly, sprinkler house floors are similar to or drier than cool cell house floors because house humidity is lower and house temperature higher, resulting in drier litter.
Water usage by cool cell systems is dependent on three factors – amount of air being drawn through the pads (this depends on number of tunnel fans running), outside temperature, and outside humidity.1 The lower the humidity (drier the air), the more water pads can evaporate, the more cooling they produce, and the more overall cooling water consumed. Dry air is key to effective evaporative cooling. This is why evaporative cooling works so well in the desert where there is very little humidity. Evaporative cooling becomes less efficient as outside humidity increases. Therefore, we do not run cool cell pads overnight or early in the morning when outside humidity is high. Once outside air becomes saturated with moisture, pads lose their ability to have a significant cooling effect.
However, water evaporating from wet cool cell pads does have a cooling effect on hot, dry air passing through the pads and alters both temperature and humidity inside the chicken house.2 It is slightly complicated and involves the First Law of Thermodynamics, but to evaporate water, heat (energy) is required. The heat comes from whatever object the water is in contact with as it evaporates; in our cool cell situation, that object is the hot outside air itself as it passes through the wet pads. As heat is removed, the temperature of the air is decreased, but the heat (energy) remains, although in another form. The First Law of Thermodynamics states that “energy can be changed from one form to another, but it cannot be created or destroyed.” We didn’t destroy the heat when we pulled it through the wet cool cell pad, we only changed its form.
Consider this: for every gallon of water that is evaporated, 8,700 Btu of sensible heat is taken out of the air (resulting in a temperature decrease) and converted to latent heat (resulting in a humidity increase). Sensible heat is related to changes in temperature; latent heat is related to changes in form (solid, liquid, gas). The decrease in air temperature of hot, dry outside air passing through wet pads must be accompanied by an increase in humidity of the now cooler (but more humid) air inside the house. We are simply trading high temperature/low humidity outside air for lower temperature/higher humidity inside air. Again, we cannot destroy that 8,700 Btu of heat per gallon of water evaporated but we can change its form by passing it through a wet cool cell pad system. However, cooling an entire chicken house consumes huge amounts of cooling water, depending on how hot and dry outside air is.
Once a flock reaches approximately four weeks of age, water use by the pads is not directly correlated with bird age. This is because with big chickens in hot weather, all or almost all the tunnel fans are operating 24/7, so the amount of air coming through the pads remains relatively constant. Therefore, daily water usage by the pads depends on how dry outside air is and has little to do with age of the birds. The high air moving capacity of today’s tunnel ventilation systems that can provide 600 to 1,000 feet per minute of air speed down the house offers the benefits of convective cooling, yet inadvertently consumes large quantities of cooling water. With big chickens in hot weather, daily cooling water demand may easily exceed daily drinking water demand.
In contrast, sprinkler cooling attempts to cool individual chickens and not the environment the chickens live in, as evaporative cooling systems do. There is no need to cool a large mass of ventilation air with cooling pads to increase convective cooling. Essentially, with sprinklers we are bluffing the chickens into thinking conditions are cooler than they are. Think of it like this. Suppose it is 100° F on a hot August afternoon and there is a breeze blowing. Now let’s suppose you go jump in the creek to cool down after hauling hay all afternoon. Once you get out of the creek, that hot breeze against your wet skin may give you chill bumps until the water evaporates. It’s still 100° F but the wind chill effect of that breeze against your wet skin has bluffed you into thinking it’s a lot cooler than that; at least until the water evaporates, and it’s time to go jump in the creek again (or get sprinkled again, if you’re a chicken).
The phase change between liquid water to water vapor that takes place on a surface (e.g., a chicken’s body that has been sprinkled) is much more efficient than convective heat transfer between chickens and the surrounding air. Cool cells and sprinklers work in entirely different ways. A cool cell system is like air conditioning, where the entire room (or a chicken house) is cooled. A sprinkler system is more like jumping in the creek and then sitting under a fan where only you (or your chickens) are cooled, not the surrounding environment.
Cooling water use by sprinkler houses during University of Arkansas trials averaged 70 percent less than cooling water use by cool-cell-only houses.3 Recent research during the summer of 2020 at Mississippi State University indicated similar results (unpublished data). In an era where water conservation is attracting global attention and locally where poultry growers may be paying high water bills or have weak wells or poor-quality water, sprinklers are a viable cooling alternative that are proven to maintain flock performance.
Commercial poultry flocks must be cooled during hot weather to maintain performance and protect bird health, safety, and welfare. Evaporative cool cell pads and large tunnel fans are the most common method to accomplish this. However, sprinklers (either alone or in combination with cool cells) have emerged as a viable cooling option but again, wind speed and airflow down the house are critical to success. Regardless of whether cool cells or sprinklers are used, wind speed and airflow are vital to keeping birds alive. The poultry industry continues to focus efforts on water conservation, reducing its carbon footprint, and minimizing its environmental impact while assisting growers with cooling their birds and protecting the health and welfare of the nation’s poultry flocks during times of heat stress and hot weather.References
DVM, PhD, MAHM
Professional Veterinarian Services
Poultry Business Unit
Boehringer Ingelheim Animal Health
Good biosecurity is a cornerstone of disease prevention in animal husbandry. The poultry industry has always been very forward-thinking in implementing and executing biosecurity plans. These plans protect our flocks by identifying possible areas of exposure, taking actions and, implementing procedures to avoid the introduction of potentially dangerous pathogens. This year, the world has seen the emergence of a dangerous human pathogen in COVID-19. Many changes have been made to the way we interact, make contact, and do business to prevent its spread. One positive benefit to the poultry industry of the new COVID-19 human biosecurity plans is the synergy that these plans have to decrease face-to-face interactions, decreasing farm visits, and thereby the risk of introduction of pathogens to our flocks.
Existing poultry biosecurity measures in farms include wearing personal protective equipment (PPE), cleaning and disinfection of materials that may be used across different locations, and the use of visitor’s identification for ease of disease tracking efforts in the event of an outbreak. But biosecurity doesn’t stop at the farm gate. We also follow these practices in other poultry company facilities, including hatcheries and live production offices. Some examples of these initiatives are footbaths or Foot Dips, sign-in, PPE (which includes plastic boots or disinfected rubber boots, coveralls, hair bonnets, and gloves etc.), limiting number of visitors and spraying tires of vehicles between locations, which are commonly used in the U.S. poultry industry. We are used to working in these conditions and that has served us well in the current pandemic conditions.
The U.S. poultry industry witnessed several disease outbreaks in the past few years, including the Avian Influenza outbreak during the fall 2014 to spring 2015. The concept of biosecurity and the implementation of company-specific programs had peaked during the period. One of the objections that limit people adhering to use proper biosecurity measures is the cost associated with the implementation and continued use of the program. In a recent webinar on Biosecurity, Dr. Karen Grogan from PDRC shared an interesting study about the comparison on the cost of biosecurity measures to disease outbreaks. The study was designed to compare the amount of money an integrator spends for biosecurity supplies (including PPE, disinfectants, bait stations, etc.) to that of a disease outbreak for ILT (including increase vaccine cost, decreased livability, increased condemnation, etc.). The cost for biosecurity supplies increased from about $60,000/million birds/year before the AI outbreak to $102,000/million birds/year post-AI outbreak. This increased sense of biosecurity limits the outbreak of other diseases such as ILT. Should there have been an outbreak of ILT, it would cost the company about $4.3 million per year due to the loss from the livability of the birds, condemnation, and vaccine costs associated with the control of the disease. So, comparing these numbers, the disease outbreak is far more costly compared to the implementation of the biosecurity measures.
During the COVID outbreak our vaccine delivery team, the Area Service Technicians, have continued to work as normal, visiting customers, and assuring vaccine supply while protecting the birds and people from disease. Some innovative actions we have seen in our customers’ hatcheries since COVID hit include having vendors call ahead to minimize cross traffic in the buildings, and requesting off-hours delivery, or increased receiving of deliveries outside the buildings to minimize contact during work hours for employees. All these procedures have been implemented while maintaining the normal measures they have in place for animal biosecurity. The agility and innovation of our team to adapt to these extra undertakings while maintaining their normally full schedules and responsibilities has been truly remarkable.
In the field, our veterinarians visit farms and attend posting sessions regularly to support our customers under strict biosecurity rules. We have seen restricted participation in posting sessions, and received and use approved disinfectants to assure our trucks are clean and sanitized between customer locations. Our biosecurity committee monitors both human and poultry disease outbreaks and provides continuing evolving guidance to our field staff on best practices for staying healthy and protecting our customers. While these policies protect us and our customers from COVID-19, they also help to maintain the lowest possible risk of a break in biosecurity to integrator’s birds.
COVID-19, while having a negative effect on many aspects of our lives has enhanced existing biosecurity plans due to less traffic and reminded us to be aware of how diseases spread. Efforts to stop the pandemic have decreased traffic, providing extra protection against poultry disease spread while allowing our essential services to remain with minimal disruption. It is human nature to let biosecurity lapse when threats are not evident. Constant work to keep biosecurity practices is important for the safety of everyone and the animals we cared for. We are grateful for the forward-thinking of our industry to allow for advanced adoption and execution of biosecurity practices.
*Footnote: We would like to thank Rodney Meyer and Craig Benich from our AST team for their contributions and insights to this article.Back to Top
Global Sales Director
The agricultural industry today is undergoing a digital revolution driven by 4 major forces: consumer demands, changes in legislation, increased focus on welfare & sustainability, and the need for improved efficiencies in our supply chains. Blockchain is one technology which has been identified as a solution to these drivers, bringing more traceability, and transparency to food chains, including poultry.
As blockchain is a decentralized and distributed ledger, it allows poultry growers, processors, brands, and retailers to share selected information across the food chain in a secure and tamper-proof manner. It is vital for agrifood companies to look for platforms that collect data from existing systems, allow for controlled sharing with third parties, and offer interoperability with other blockchain platforms.
By providing a single, unified source of data, a traceability platform based on blockchain creates consistency across parties, along with a clearer audit trail.
Blockchain platforms can also integrate data from IoT sensors, such as GPS locations, delivery truck temperatures, or even integrate microbiological analysis results, such as Salmonella. Information regarding veterinary interventions can also be collected and included.
Additional smart technologies can also be combined with blockchain to ensure the quality of the data being recorded. Unlike other blockchain technology, Connecting Food is able to fully tap into this potential with its proprietary digital solution which audits 100% of the food chain, comparing data in real-time to product specifications, and sending out live alerts if certain audit criteria are not respected.
By using blockchain to perform real-time audits, poultry producers, processors, and brands can drastically reduce the risk of a product recall by identifying problems as they occur, increasing consumer safety while limiting losses to both brand image and the bottom line. This is one of the reasons why there is hope that blockchain will facilitate 31 billion dollars in food fraud savings by 2024 (following a recent study by Juniper research).
Italy’s largest retailer Coop Italia is using blockchain to track and audit the 250 000 Vivi Verde organic eggs produced daily on their “Coopchain”.
Internally, the solution enables them to manage traceability and get real-time alerts regarding the freshness of their eggs, their producers’ certificates, and their Salmonella test results.
Externally, they leverage their data via a QR code, which allows consumers to verify for themselves that the product they have in their hands is truly organic and free-range, as well as discover the eggs’ entire journey from farm to store.
A few initial poultry blockchain tests have been run in the U.S., but the industry as a whole is currently behind other sectors (beef, pork, etc.) in the adoption of this new technology. The high number of recent poultry-related recalls however have consumer confidence lagging, and there are real opportunities today for forward-thinking poultry producers and brands to position themselves as the industry leaders in transparency.Back to Top
While fans generally get the blame for poor summer ventilation performance, in some cases, it is the evaporative system on the other end of the building that is the culprit. Dirty pad openings can restrict airflow, and uneven water distribution causes streaking resulting in inconsistent cooling. The right procedures at spring startup can prevent problems later this summer.
Over the winter, insects, dirt, and dust have probably collected on the pad clogging up the flues. Using a high-pressure sprayer will cause damage to the pads. Instead, use a low-pressure hose-end sprayer to flush away debris along with a soft-bristled brush for any heavy accumulations. Do not use bleach or other chlorine-based cleaners that will destroy the pad material.
Remove any sand or debris from troughs.
Check pads for physical damage from rodents and insects. Look for soft areas along the bottom of the pads that can cause the pads to sag. Sagging pads reduce the amount of cooled air entering the buildings by allowing it to "short-circuit" through gaps instead of passing through the pads.
Take a few of the pads out and remove any sand or dirt buildups from the bottoms of the trough. Inspect the areas where the troughs join together for gaps or missing caulk. Check for trough supports that might have come loose from the wall.
Remove the sump or jet pump from winter storage (because you didn't leave it in the tank all winter) and clean out any debris from the strainer basket and body pump head. Open the filter body and clean the screen inside before installing the pump unit on the supply plumbing.
Too high of water level in the trough leads to pad bottoms getting soft and sagging.Back to Top
MSc., MBA Agriculture
Global Animal Partnership
In 2016, Global Animal Partnership (G.A.P.) announced its intention to move beyond growth rate as a determinant of eligibility in their 5-Step® Animal Welfare Certified Program and focus on breeds that met specific high welfare outcomes. G.A.P. had been hearing from producers that the modern commercial broiler breeders were harder to grow than ever, that the prevalence of woody breast and white striping was becoming a significant customer issue, and that maybe the drive for efficiency and breast meat yield had gone just a little bit too far.
Currently, fast-growing chicken breeds represent roughly 98 percent of all commercially available chicken meat in North America, if not the entire world. Modern chickens have been genetically selected for their fast, efficient growth and higher yield of breast meat. However, this has had unintended detrimental impacts on their welfare resulting in limitations to the bird’s ability to express natural behaviors like perching, flying, and even walking.
G.A.P. already knew that animal welfare was impacted by genetics, so it seemed the perfect opportunity to take a hard look at the broiler breeds approved for use in its standard. Intent on leveraging its diverse partner base, with over 350 million broiler chickens certified to the G.A.P. Program annually, its multi-tiered standard, and its commitment to using science-based evidence to inform its standards writing process, G.A.P. started to map how it could actually support and make a change with the breeds approved for use in the G.A.P. program.
G.A.P. was aware that despite compelling evidence of problems with commercial broiler genetics, it wasn’t a complete picture, and the organization felt this level of change really needed a different, multi-disciplinary approach. G.A.P.’s solution was a scientific study that would look not only at animal welfare and behavior, but meat quality, anatomy, physiology and other production measures. With such a wide scope, G.A.P. knew that of the many possible research facilities, the University of Guelph, Ontario had the best expertise – with world renowned animal scientists and the necessary facilities to complete the research.
After seeking public input from a variety of stakeholders, G.A.P. provided a document to the University of Guelph researchers outlining its goals for the study, and suggested areas of importance. With input from the breeding companies, the University then designed and conducted the study, using its own expertise and objectivity.
In 2017, led by researchers Drs. Stephanie Torrey and Tina Widowski, the University of Guelph embarked on the two-year research project to evaluate the parameters necessary for assessing the animal welfare needs of different genetic strains of chicken breeds. Three major broiler genetic companies, as well as a few proprietary breeds, supplied genetics to the study.
The study was designed and conducted independently at the University of Guelph and included more than 7,500 broiler chickens from 16 different genetic strains.
“No other broiler chicken welfare research project has been done on this scale,” said Dr. Widowski. “This was the first multi-disciplinary research project of chicken welfare to include carefully chosen indicators such as behavior, physiology, anatomy, production, and meat quality together into one research project.”
“Throughout G.A.P.’s history as an animal welfare certification program, we have continued to pioneer innovative improvements to how animals are raised, and led and cared for; however, regardless of how well broiler chickens are reared, there’s still an issue with the birds themselves. Our vision is to use the findings from this study to identify multi-disciplinary factors that could objectively support change within our existing standards program,” said Anne Malleau, G.A.P. Executive Director.
Based on the final results of the Guelph study completed this year, a multi-stakeholder technical working group of experts has been assembled to assist G.A.P. with drafting protocols for assessing breeds for use in their program in the future. G.A.P. will name the first line of approved breeds upon completion of the broiler assessment protocol later next year.
A summary of the study results is available to the public by accessing G.A.P.’s Better Chicken Project page here. All results from the study will eventually be published in peer-reviewed journals by the researchers involved in the study, and additional analysis and further data will be released in the future.
A key finding of the study is that even under controlled conditions with excellent management, fast-growing broiler chickens face significant animal welfare trade-offs such as less activity and poorer mobility, higher rates of muscle myopathies (e.g., woody breast, white striping), and potentially inadequate organ development.
“Implementing this kind of transition will require significant work, but we are confident that this new direction will bring more benefit to birds, producers, consumers and food purveyors alike,” said Malleau.
As hundreds of large food and hospitality companies have pledged to address broiler chicken welfare as part of their corporate social responsibility commitments, G.A.P. offers a path toward meeting those promises with its highly regarded animal welfare certification and labeling program. Consumers should beware of vague or undefined claims of chicken welfare: by looking for the G.A.P. Animal Welfare Certified label, they will know they are buying chicken raised to science-based welfare standards and verified by a third-party Certifier on every farm.
G.A.P. secured funding for the project, and the researchers secured additional funding from the Canada First Research Excellence Fund. In-kind contributions were provided by Ontario Agri-Food Innovation Alliance and major poultry genetics companies.
Global Animal Partnership is one of the largest animal welfare standards and labeling organizations in North America. Established in 2008, G.A.P. impacts the welfare of over 416 million animals each year through third-party certification of more than 3,900 farms, supplying products to over 5,000 outlets. G.A.P. believes that meaningful label claims, validated by third-party audits on every farm, are key to influencing the industry, raising consumer expectations, and creating long-lasting change for farm animals. Visit globalanimalpartnership.org to learn more.Back to Top