The present invention provides a feather treatment process through hydrolytic reaction, which gives rise to a hydrolyzate containing amino acids, wherein the invention is characterized in that feather is subjected to hydrolysis in the environment of a reaction mixture containing water and carbon dioxide in weigh ratio of the carbon dioxide to water 1:50 to 1:10, at a temperature in the range of 100 to 200 degC and at a minimum pressure from 1 MPa. After finish of hydrolysis, the obtained suspension is separated into a liquid and solid phases, whereby the liquid phase is then used for the preparation of a fertilizer while the solid phase is used as a feed or as an organic fertilizer.