Urban Agriculture in Motion: Chickens are the plow in food production at CIÊNCIAS

António Vaz Pato, Joana Sanders, Renata Reynaud and David Avelar

1 April, 2025

The story of the mobile chicken coop at PermaLab, part of HortaFCUL, is a living example of how permaculture principles can transform challenges into opportunities. Since its implementation in 2018, this mobile chicken coop, or chicken tractor in English, has been designed to unite sustainability, innovation, and community, playing a key role in the project's agricultural ecosystem.

A chicken tractor is a henhouse that can move from plot to plot, housing native breeds of chickens. It serves to weed plots, compost organic waste, feed chickens with vegetable scraps from the garden, produce eggs, till and fertilize agricultural soil, bring life and community spirit to the PermaLab, and analyze its success using scientific methods.

Initially built with wood and recycled materials, the chicken tractor was integrated into a crop rotation system, utilizing organic waste from CIÊNCIAS.

The first chicken tractor structure, built in the early years of PermaLab with recycled wood and metal netting. Documentary work from Marissa Verhoeven's internship on vermicomposting (2019). Source: HortaFCUL

As inhabitants of this system, the chickens contributed significantly to fertilizing the soil with their droppings, aerating it while foraging for food, and also laying eggs, which they shared during the garden's workdays. The illustration accompanying the article explains a bit about the food production cycle and the revaluation of waste by the chickens in the PermaLab.

Diagram of the operation of the chicken tractor in the PermaLab agricultural ecosystem. (1) After harvesting a plot, organic waste from bars and cafeterias is added to, on the one hand, provide food for the chickens and, on the other hand, directly compost this waste with the help of the chickens; (2) the chicken tractor is placed in the plot so that the chickens can do their work of preparing the soil for the following planting and sowing, taking advantage of this time to collect the dividends in eggs; (3) after nourishing the soil, it is time to sow and plant our agricultural crops; (4) after additional fertilization with worm castings and nettles, our vegetables are ready to be harvested to feed the Horta community and share the surplus with the CIÊNCIAS community. Illustration by guardian Renata Reynaud. Source: HortaFCUL

However, this journey had numerous challenges. In 2019, the arrival of Lusitanian Black chickens, donated by Herdade do Freixo do Meio, brought increased efficiency to the system, but also the need to reinforce the infrastructure. Space and comfort problems began to emerge, and the need for a more durable solution became evident. It was then that the project “CHILL - Chicken Tractors as an efficient and sustainable Link in closed Loop agriculture” was born, the result of an honorable mention in the 2022 edition of the Ideas for Sustainability Competition, which introduced a new version of the chicken coop, built in aluminum, lighter and more durable, and equipped with a thermally insulated henhouse.

Despite the improvements, the henhouse faced a series of devastating setbacks in the following years. At the end of 2022, a flock of chickens was attacked by dogs from the neighboring racetrack. In 2023, similar episodes occurred, even after reinforcements to the structure, culminating in a robbery by another gang. These incidents led HortaFCUL to seek more robust solutions and, with the support and sponsorship of the CIÊNCIAS Faculty Board, Horta was able to acquire the necessary materials to reinforce the fence and ensure the well-being of the flock.

New chicken coop with reinforced infrastructure, made of an aluminum alloy, with a weather-protected section where the chickens shelter and sleep. Predator-proof and theft-proof structure. Source: HortaFCUL

Furthermore, in order to create and foster synergies with research institutes, HortaFCUL contacted the Center for Poultry Biodiversity of the Instituto Superior de Agronomia, led by Professor Madalena Lordelo, to establish a partnership that would enhance the project and the crucial role of these animals in the agricultural ecosystem.

Thanks to this collaboration, in 2025, Horta received a new flock of native chicken breeds (speckled hen and Minho white hen).

This reintroduction symbolizes a rebirth for the project.

The new flock of chickens of CIÊNCIAS has already settled into the newly renovated chilling room: one rooster and three hens of the Portuguese Pedrês breed and two hens of the Minho White breed. Source: HortaFCUL

The journey to this point hasn't been easy, but the community's resilience has shown that every challenge can be overcome with creativity and unity. The new, safer, and more efficient chicken tractor symbolizes the hope for a more sustainable future for the project. May the lessons learned serve as inspiration for others, proving that, even in the face of adversity, collaboration and innovation can always open new doors.