The study aimed to investigate adult chinchillas’ preferences when choosing between cages with different floor areas, heights, or both. The size of the cages with a larger floor area was double that of the standard-sized cages in the farms (0.25 and 0.50 m²), while their height was 2.4 times that of the standard-sized cages (0.4 and 1 m). The chinchillas (10–14 in each cohort) were housed in blocks of cages where they could move freely between the smaller and larger cages. The chinchillas’ location preferences were monitored continuously over five days using infrared video recording. The chinchillas were observed in the cages with smaller floor areas 1.9 and 2.7 times more frequently than in the larger ones (p < 0.001) during the dark (active) and light (resting) periods of the day, respectively. When the cage height was 0.4 m, they chose it 3.4 and 6.7 times more frequently, respectively, than the cage that was 1 m high (p < 0.001). When both the floor size and the height were increased, the chinchillas still favored the smaller and lower cages (p < 0.001). The study findings suggest that adult chinchillas show a preference for smaller and shorter cages when the small and large cages are not environment enrichment barren, especially during the rest period of the day, even when the floor area, height, or both are increased. In the future, it would be important to investigate different forms of cage enrichment.

This study investigated the cage size preferences of juvenile chinchillas using enclosures that allowed free choice between different dimensions. Three comparisons were tested: (1) small floor area (0.15 m²) vs. double floor area (0.30 m²) at constant height; (2) low height (0.4 m) vs. high height (1.0 m) at constant floor area (0.15 m²); and (3) small–low cage (0.15 m² × 0.4 m) vs. large–high cage (0.30 m² × 1.0 m). The juveniles consistently preferred the smaller or lower enclosures across all trials. In the floor area tests, chinchillas spent about 66–75% of their time in the small cage compartments (p < 0.001). In the height comparison, the low cage was preferred by 70% (p < 0.001). When both floor area and height were increased, the small–low cage was preferred by 79% (p < 0.001). Differences in preference were most evident during the daytime period. At night, however, cage utilization was more even. These results indicate that young chinchillas strongly prefer smaller, lower spaces. Based on these preference tests alone, simply providing larger cages (without other modifications) did not result in greater use by juvenile chinchillas. These unexpected results suggest that factors such as safety or familiarity drive juveniles to choose smaller enclosures. Further research is needed to clarify the motivation behind these preferences and to determine how best to incorporate them into improved welfare-oriented housing designs.