Objective The present study aimed to establish a chicken model of fatty liver hemorrhagic syndrome (FLHS) induced by a combination of injection of estrogen and feeding of high fat diet, and to evaluate the clinical symptoms, blood lipid levels, liver function and pathomorphology of these chicken models. MethodsThree hundred twenty 14 day-old Cyan-Shank Partridge chickens were randomly divided into 4 treatment groups (4 replications of 20 birds in each group):Control (C), high-fat diet (HF), estrogen injection (E), and high fat diet plus estrogen injection (HF+E) groups. The experimental period lasted from 15 to 42 days. Two 14-day periods were used to assess different factors. The clinical symptoms of the chickens were monitored each day over the experimental period. Abdominal fat weight, pathological changes, serum and liver parameters were measured at the end of each 14-d periods. ResultsFLHS occurred in the group HF+E at 14^th day whereas FLHS didn’t occur in the control group till 28^th day. The group HF+E showed obvious clinical symptoms such as mouth breathing, excessive sleepiness and abdominal sag in some birds 10 days later. Excessive fat deposition in the abdominal cavity and swollen, brown-yellow, friable, blunt and hemorrhagic liver were observed on day 14 and 28. Slight hepatocyte steatosis and small lipid vacuoles in cytoplasm were observed on day 14. A large number of hepatocytes displayed distinct pathological changes such as histological disarrangement, swelling and large lipid vacuoles in cytoplasm on day 28. The FLHS incidence was higher at 28^th day compared with that on the 14^th day. The serum triglyceride and total cholesterol, the relative weight of liver and abdominal fat, liver fat rate and liver hemorrhage score (LHS) were increased significantly compared with those in the control group on day 14 and 28 ( P<0. 05, P<0.01). The clinical symptoms, anatomic characteristics, pathological changes, blood biochemical indices and other findings in the group E and HF were similar to those in the group HF+E, but to a less severe degree and the time of occurrence was later than that in the group HF+E. ConclusionThe results of this study suggest that high fat diet combined with estrogen administration can successfully establish model of fatty liver hemorrhagic syndrome in immature chickens within 28 days.