D-Lab off-grid brooder saves chicks and money using locally manufactured thermal batteries
MIT D-Lab students and instructors are improving the efficacy and economics of a brooder technology for newborn chicks that utilizes a practical, local resource: beeswax.
Developed through participatory design with agricultural partners in Cameroon, their Off-Grid Brooder is a solution aimed at improving the profitability of the African nation’s small- and medium-scale poultry farms. Since it is common for smallholders in places with poor electricity supply to tend open fires overnight to keep chicks warm, the invention might also let farmers catch up on their sleep.
“The target is eight hours. If farmers can sustain the warmth for eight hours, then they get to sleep,” says D-Lab instructor and former student Ahmad (Zak) Zakka SM ’23, who traveled to Cameroon in May to work on implementing brooder improvements tested at the D-Lab, along with D-Lab students, collaborators from African Solar Generation (ASG), and the African Diaspora Council of Switzerland – Branch Cameroon (CDAS–BC).
Poultry farming is heavily concentrated in lower- and middle-income countries, where it is an important component of rural economies and provides an inexpensive source of protein for residents. Raising chickens is fraught with economic risk, however, largely because it is hard for small-scale farmers to keep newborn chicks warm enough to survive (33 to 35 degrees Celsius, or 91 to 95 degrees Fahrenheit, depending on age). After the cost of feed, firewood used to heat the chick space is the biggest input for rural poultry farmers.
According to D-Lab researchers, an average smallholder in Cameroon using traditional brooding methods spends $17 per month on firewood, achieves a 10 percent profit margin, and experiences chick mortality that can be as high as a total loss due to overheating or insufficient heat. The Off-Grid Brooder is designed to replace open fires with inexpensive, renewable, and locally available beeswax — a phase-change material used to make thermal batteries.
ASG initially developed a brooder technology, the SolarBox, that used photovoltaic panels and electric batteries to power incandescent bulbs. While this provided effective heating, it was prohibitively expensive and difficult to maintain. In 2020, students from the D-Lab Energy class took on the challenge of reducing the cost and complexity of the SolarBox heating system to make it more accessible to small farmers in Cameroon. Through participatory design — a collaborative approach that involves all stakeholders in early stages of the design process — the team discovered a unique solution. Beeswax stored in a used glass container (such as a mayonnaise jar) is melted using a double boiler over a fire and then installed inside insulated brooder boxes alongside the chicks. As the beeswax cools and solidifies, it releases heat for several hours, keeping the brooder within the temperature range that chicks need to grow and develop. Farmers can then recharge the cooled wax batteries and repeat the process again and again.
“The big challenge was how to get heat,” says D-Lab Research Scientist Daniel Sweeney, who, with Zakka, co-teaches two D-Lab classes, 2.651/EC.711 (Introduction to Energy in Global Development), and 2.652/EC.712 (Applications of Energy in Global Development). “Decoupling the heat supplied by biomass (wood) from the heat the chicks need at night in the brooder, that’s the core of the innovation here.”
D-Lab instructors, researchers, and students have tested and tuned the system with partners in Cameroon. A research box constructed during a D-Lab trip to Cameroon in January 2023 worked well, but was “very expensive to build,” Zakka says. “The research box was a proof of concept in the field. The next step was to figure out how to make it affordable,” he continues.
A new brooder box, made entirely of locally sourced recycled materials at 5 percent of the cost of the research prototype, was developed during D-Lab’s January 2024 trip to Cameroon. Designed and produced in collaboration with CDAS-BC, the new brooder is much more affordable, but its functionality still needs fine-tuning. From late-May through mid-June, the D-Lab team, led by Zakka, worked with Cameroonian collaborators to improve the system again. This time, they assessed the efficacy of using straw, a readily available and low-cost material, arranged in panels to insulate the brooder box.
The MIT team was hosted by CDAS-BC, including its president and founder Carole Erlemann Mengue and secretary and treasurer Kathrin Witschi, who operate an organic poultry farm in Afambassi, Cameroon. “The students will experiment with the box and try to improve the insulation of the box without neglecting that the chicks will need ventilation,” they say.
In addition, the CDAS-BC partners say that they hoped to explore increasing the number of chicks that the box can keep warm. “If the system could heat 500 to 1,000 chicks at a time,” they note, “it would help farmers save firewood, to sleep through the night, and to minimize the risk of fire in the building and the risk of stepping on chicks while replacing firewood.”
Earlier this spring, Erlemann Mengue and Witschi tested the low-cost Off-Grid Brooder Box, which can hold 30 to 40 chicks in its current design.
“They were very interested in partnering with us to evaluate the technology. They are running the tests and doing a lot of technical measurement to track the temperature inside the brooder over time,” says Sweeney, adding that the CDAS-BC partners are amassing datasets that they send to the MIT D-Lab team.
Sweeney and Zakka, along with PhD candidate Aly Kombargi, who worked on the research box in Cameroon last year, hope to not only improve the functionality of the Off-Grid Poultry Brooder but also broaden its use beyond Cameroon.
“The goal of our trip was to have a working prototype, and the goal since then has been to scale this up,” Kombargi says. “It’s absolutely scalable.”
Concurring that “the technology should work across developing countries in small-scale poultry sectors,” Zakka says this spring’s D-Lab trip included workshops for area poultry farmers to teach them about benefits of the Off-Grid Brooder and how to make their own.
“I’m excited to see if we can get people excited about pushing this as a business … to see if they would build and sell it to other people in the community,” Zakka says.
Adds Sweeney, “This isn’t rocket science. If we have some guidance and some open-source information we could share, I’m pretty sure (farmers) could put them together on their own.”
Already, he says, partners identified through MIT’s networks in Zambia and Uganda are building their own brooders based on the D-Lab design.
MIT’s Abdul Latif Jameel Water and Food Systems Lab (J-WAFS), which supports research, innovation, and cross-disciplinary collaborations involving water and food systems, awarded the Off-Grid Brooder project a $25,000 research and development grant in 2022. The program is “pleased that the project’s approach was grounded in engagement with MIT students and community collaborators,” says Executive Director Renee Robins. “The participatory design process helped produce innovative prototypes that are already making positive impacts for smallholder poultry farmers.”
That process and the very real impact on communities in Cameroon is what draws students to the project and keeps them committed.
Sweeney says a recent D-Lab design review for the chick brooder highlighted that the project continued to attract the attention and curiosity of students who participated in earlier stages and still want to be involved.
“There’s something about this project. There’s this whole tribe of students that are still active on the broader project,” he says. “There’s something about it.”
