Abstract: Abstract: 【OBJECTIVE】This trial was conducted to study the importance of insulin, leptin, NPY and α-MSH in the regulation of feed intake in newly-hatched chicks, and mechanism of feed intake difference among different genotypes.【METHOD】Changes of feed intake, serum insulin and leptin, hypothalamic insulin, leptin, NPY and α-MSH during 11 days posthatching in Peking and AA chicks were observed.【RESULTS】Developmental changes of serum and hypothalamic hormone levels with age differed in genotypes and parameters. Serum insulin levels of Peking and AA chicks at 0 day were lower than that at 1~11 days. Serum leptin level of AA chicks at 0 day was also lower than that at 1 and 3 days; however in Peking chicks, serum leptin level at 0 day was similar to that at 1 day, and slightly higher than those at the other ages. Correlation analysis showed that ADFI showed high correlations with serum leptin, hypothalamic insulin, lepin and NPY levels, but there were no correlations between ADFI and serum insulin or hypothalamic α-MSH levels. Comparative results between lines showed that serum insulin level at 1 day, serum leptin levels at 1 and 3 days, and hypothalamic α-MSH level at 0 day of Peking chicks were significantly lower than that of AA chicks, but serum insulin levels at 0 and 11 days of Peking chicks were the opposite, and there were no differences in serum and hypothalamic hormone levels of the other days between Peking and AA chicks.【CONCLUSION】Insulin and leptin could play a role in regulation of feed intake in newly-hatched chick, but the parameters observed did not explain why there was significant difference in feed intake between Peking and AA chicks. Therefore, further studies are needed to elucidate mechanisms of regulating feed intake of newly-hatched chicks and feed intake difference between different genotypes.