Social change requires new educational planning and sustainable teaching methods. Shaping an environment of care with animals as a part of the daily school life may produce such a change. In this article, we present a transdisciplinary study with the aim of exploring whether raising chickens in a classroom could promote learning, especially sustainability learning, and how. The study employs an ethnographic approach and we have analyzed the data according to interaction analysis. We collected the data in a culturally-diverse Finnish primary school class during May 2018. The data comprise field notes, videos and photographs from indoor and outdoor school activities; interviews and discussions with teachers and students; and, texts and artifacts that were made by students. The results show that having chickens in the classroom not only improved the students’ learning of biology, but also enhanced many other activities. The chicken project became part of a complex learning culture that met several of the aims of the curriculum and in many ways reached beyond the aim of merely learning science. The project became a natural part of sustainability education and promoted the acquisition of knowledge and skills in relation to the ecological and social dimensions of sustainability.