This study was conducted to bioassay of amino acid availability of feather meal processed by a different methods, commercial feather meal and raw feather meal, The feather meals were processed by labolatory pressure cooker(autoclave) at 2kg/$ extrm{cm}^2$ for 30 minutes ; 3kg/$ extrm{cm}^2$ for 90 minutes : 4kg/$ extrm{cm}^2$ for 120 minutes. Chick employed in the present experiment were Abor Acre strain, male or meat type (body weight, 100-140g), fed with semipurified diet and protein free diet was given during the determination of the metabolic and endogeneous amino acid. The contents of amino acid of samples were investigated by ion-exchange chromatography. The results were as follows; 1. The amino acid availability of raw, 2kg/$ extrm{cm}^2$ for 30 minutes, commercial, 4kg/$ extrm{cm}^2$ for 120 minutes and 3kg/$ extrm{cm}^2$ for 90 minutes of feather meal were -3.09, 63.28, 67.47, 71.22 and 73.75% respectively. 2. The essential amino acid availability of raw, 2kg/$ extrm{cm}^2$ for 30 minutes, commercial, 4kg/$ extrm{cm}^2$ for 120 minutes and 3kg/$ extrm{cm}^2$ for 90 minutes of feather meal were 2.55, 66.78, 66.89, 72,56 and 73.62%, respectively. 3. In individual amino acid of the different processing loather meal and commercial feather meal, biovailabilities were increased methionine, phenylalanine, leucine, arginine, threonine, isoleucine, however, histidine, lysine and aspartic acid were remarkely decreased. In conclusion, the bioavailability or amino acid for the feather meal processed at 3kg/$ extrm{cm}^2$ for 90 minutes was superior to those of other treatment or raw feather meal.