One might not expect to find eleven immaculately painted plaster chicken heads in a museum of the history of science such as the Whipple Museum. The heads were made in the early 1930s and have been attributed to Reginald Punnett, Alfred Balfour Professor of Genetics at the University of Cambridge from 1912 to 1940. During his long career, Balfour conducted detailed breeding experiments with chickens, experiments that are themselves bound up with the invention for which he is best known today, the Punnett square, a tabular array still used in genetics to represent the outcome of a cross between two organisms. In this chapter, I investigate how both Punnett’s square and his chicken head models, qua visualisations, played different but related roles in the study and teaching of Mendelian genetics and heredity during this crucial period in the development of genetics in Britain. In so doing, I demonstrate that models and their uses in science are most clearly illuminated when their relations to and differences from other forms of visual media, including flat material such as the Punnett square, are made clear.