Experimenting with shed design to reduce heat stress in livestock, poultry

On a hot summer day in 2020, Savitri Bhanse went to tend to her chickens in her small backyard farm. But her ordinary routine of checking and feeding her chickens was upended by a crisis that spiralled out of control. “Some 50 to 70 chicks died in one day, just like that. They couldn’t survive because of the heat,” she told Mongabay India.

It was her second year rearing chickens with the Kesla Poultry Society, a cooperative of tribal women poultry farmers operating in Narmadapuram district (formerly Hoshangabad) in Madhya Pradesh, and the first time she’d experienced a loss of this kind in one fell swoop.

Extreme heat can be deadly for poultry and livestock. Poultry makes up 50% of India’s total meat production, while dairy contributes 24% to the country’s agriculture sector. Together, dairy and animal husbandry make up 4.5% of India’s total Gross Domestic Product (GDP). But extreme heat is challenging productivity in these sectors, which are set to grow as India’s population rises.

Commercial farms with more capital are better equipped to mitigate the impacts of heat stress, with some providing industrial-scale air ventilation systems in their sheds. Smaller and marginal farmers like Bhanse, are more at risk of experiencing losses in productivity or mortality on account of high temperatures. “Among the total agriculture households in India, 89.4% or 83.2 million are from small and marginal agriculture households. Small and marginalised farmers in India, post the Green Revolution, have seen degradation of soil, declining yield and furthering climate stressors without reaping the benefits,” said Nirmita Chandrashekar, senior program manager at SELCO Foundation, a social energy enterprise delivering sustainable energy solutions for the poor.

Small interventions such as changing roofing material or shed design can be life-saving for livestock exposed to heat in the summer months. Savitri Bhanse, who owns 500 chickens, credits the installation of a solar-powered cooler in her farm for preventing losses like the one she faced in 2020.

On the boil

The optimum ambient temperature for chickens is between 15 and 25 degrees Celsius and heat stress can set in when ambient temperatures rise to 30 degrees or higher. This causes their already high internal temperature of 41 to 42 degrees to shoot up. In the absence of sweat glands, chickens have limited avenues to release the heat building up in their bodies. If internal temperatures cross 46 degrees, heat stress in chickens can be fatal.

Similarly, livestock like cows and pigs thrive when ambient air temperatures are between 15 and 27 degrees Celsius. “Cows have a lot of metabolic heat, which comes from energy released from food consumption. If there’s an overload of heat, it causes an imbalance of microbes in the body which prevents proper digestion and leads to discomfort in the animal. It will begin to pant to try and expel the heat. If the heat cannot be offloaded, it builds up and causes stress,” explained Teja Reddy, lead manager of veterinary services at Akshayakalpa, an organic dairy enterprise based in Karnataka.

This year’s summer is expected to be especially severe, with extreme heat projected in most parts of the country through April, May and June. Heatwaves over India have increased in duration by 2.5 days between 1961 and 2021 due to global warming, according to the India Meteorological Department. Climate change is likely to make heat waves longer, more frequent and more intense over the next few decades if warming continues at current rates. A study in the Lancet projected milk production could reduce by as much as 25% in India’s arid and semi-arid regions by 2085 due to global warming.

Pigs, too, are less productive at high temperatures. Compared to those maintained at 21 degrees, pigs exposed to 32 degrees Celsius were found to consume between 60-100 grams less with every degree rise, corresponding to a decrease in body weight gain of 35 to 57 grams per day, per degree rise.

The resulting impact on farmers spells a direct loss in income. Savitri’s neighbour, Sushila Parthe, has been rearing chickens since 2008 and doesn’t have a cooler for her flock of 1000, instead managing with a thick thatched roof and an airy shed. While she hasn’t dealt with high mortality, her chickens suffer from low weight over the summer months, she told Mongabay India. Low weight gain, coupled with reduced demand during auspicious Hindu months like Sawan, which call for the abstinence of meat, means the loss is doubly worse for farmers like her. “During the summer, I only earn Rs. 7,000 or Rs. 8,000 per batch, compared to the winter, when I’m able to make between Rs. 12,000 to Rs. 14,000,” she said, adding, “Those months are difficult, but I manage because my children send money home.”

Harekrishna Deka, managing trustee and chief operating officer of the National Smallholder Poultry Development Trust (NSPDT), a country-wide network of smallholder rural women poultry farmers, told Mongabay India that 95% of chickens sold in India are sold live, where weight plays an important role. “Where there are no coolers, we try to make interventions in other areas, like replacing asbestos sheets with thermally insulated ones or solar-operated fans to reduce the build up of gasses in the sheds,” he said.

Other measures, like sprinkling water on cages, ensuring the animals have enough drinking water and soaking gunny bags and laying it on roofs or the bodies of animals are popularly employed techniques by farmers to stay cool, but are temporary in nature.

Improving shed design

The solar operated cooler used by Savitri was given to her by SELCO Foundation, through their Sustainable Energy led Climate Action Program (SELCAP). Thermal discomfort can arise from poor shed design, unhygienic and cramped conditions and cheap but heat absorbing roof materials like asbestos, said Chandrashekhar. The Foundation partnered with the NSPDT to develop solutions for temperature regulation, including distribution of coolers and experiments with roofing materials.

The Kesla Poultry Society, under the NSPDT, distributed around 400 solar-operated coolers in the Narmadapuram (Hoshangabad) district and studied how they impacted farmers compared to farms without coolers. They found that the coolers saved Rs. 2.17 per kg in production costs, resulting in savings of over Rs. 9,37,641 in total for the Society. “A producer with cooler installed sheds was paid an average of Rs. 5,233 in a batch whereas producers without coolers were paid an average Rs. 4,312 in a batch,” the analysis, shared with Mongabay India, said. The average flock size per batch was 500-700 birds, in a cycle of 35-38 days.

Positive as the results have been, the capital cost of purchasing and installing the cooler is still prohibitive for smallholder farmers, said Deka. The high cost, at around Rs 40,000 per cooler, has been the biggest bottleneck in scaling up their installation. In the absence of coolers, other solutions, like solar operated ceiling fans are being installed in other farms.

Siddalingaswamy, a dairy farmer from Madarasabpalya village in Karnataka’s Tumakuru district plans on experimenting with his shed design to allow more cross ventilation for his 20 cows. Siddalingaswamy is a farmer with Akshayakalpa. “I’ve been a dairy farmer for the last four years, but I only felt the need to install shade and foggers this year due to the heat,” he told Mongabay India, adding, “The foggers are only helping reduce the heat stress by a small margin, so I will try replacing my asbestos roof with zinc and increase the length of the shed to eight feet, with height of ten feet.”

Akshayakalpa supports its farmers with shed design in order to optimize milk yields, said Rajeev Krishnamurthy, a development engineer at Akshayakalpa. “We use architectural planning, HVAC system design and considerations for natural ventilation to come up with initial designs for sheds and their prototypes,” said Krishnamurthy. The designs are modified through an iterative process before being piloted and eventually scaled. “These sheds often incorporate features like natural ventilation, proper lighting, and comfortable flooring to enhance the well-being of dairy cows.”

An internal analysis by Akshayakalpa from 2016 to 2022 shows that in each year, average daily yields per cow in their specially designed sheds gave between 1.2 litres and 3.7 litres more milk compared to conventional sheds. In addition to higher yields, the sheds are also cheaper to construct, according to the analysis. The cost of setting up a conventional closed shed is Rs. 3,20,725. An open shed using Akshayakalpa’s design can be constructed for Rs. 1,70,000. “Over time, this increased productivity could offset the initial construction costs and provide economic benefits,” said Krishnamurthy.

The next frontier is establishing a model to fund decentralized renewable energy projects so they are affordable for marginalized farmers, said Chandrashekhar. Zero interest loans, subsidies through National and State Rural Livelihood Missions, or carving out allocations within the District Mineral Foundations or Watershed Development Funds are some of the ways these projects can be integrated to support other development agendas. “We have the evidence, so now the question is how do you build enough consensus for more scale to happen? One approach is to look at national animal husbandry and veterinary departments or ministries to see how this type of intervention can be combined with existing programmes,” she added.

Banner image: Sushila Parthe, a poultry farmer with the Kesla Poultry Society, tends to her chickens. Photo by Bablesh Maskole/Kesla Poultry Society.