The objective of this study was to establish a low-bacteria intestinal model in chickens, and then to investigate the characteristics involving in immune function and intestinal environment of this model. A total of 180 twenty-one-week-old Hy-line gray layers were randomly allocated into 2 treatment groups. Hens were fed with a basic diet (Control), or an antibiotic combination diet (ABS) for 5 weeks. Results showed that the total bacteria in the ileal chyme were significantly dropped after ABS treatment. Compared with the Control group, the ge...