Color is one of the perch properties. This study was conducted to investigate the general behaviors and perching behaviors in laying hens under different group size (stocking density), and to understand the perch color (black, white or brown) preference of hens during the night. A total of 390 Hyline Brown laying hens was used, and randomly allocated to three treatments: individual group (G1), group of four hens (G4), and group of eight hens (G8), respectively. There were 30 replicates in each group. The hens in G1, G4 and G8 groups were put into the test cages in which three colored perches were simultaneously provided and allowed for four days of habituation in the new cages. Hens behaviors were recorded using cameras with infrared light sources for the following periods: 8:00 to 10:00; 14:00 to 16:00; 19:00 to 21:00; 23:30 to 0:30 on the fifth day after transferring the birds into the test cages. The behaviors of hens in every time period were collected and analyzed, and hens positions on the test perches during mid-night were recorded. The results showed that, group size (stocking density) had significant effect on most of the general behaviors of laying hens except exploring behavior. There were great differences in most of the general behaviors during different time periods. In the preference test of perch color during night, the hens showed no clear preference for white, black or brown perches. For perching behaviors, perching time and frequency of transferring from one perch to another was higher on black perches than on white or brown perches in individual groups. In G4 groups, the hens spent more time on white perches during daytime and more frequent transferring during night compared with black or brown perches. The frequency of jumping upon and down from white perches was higher in G8 groups. It can be concluded that although the group sizes in the cage significantly affected most of the general behaviors, we found that no preference of perch color was shown by the caged laying hens in the different group sizes tested in this study.
