Feeding trials were designed to evaluate the nutritive value of feathers treated by a feather-degrading bacterium, Bacillus licheniformis (Strain PWD-1). An initial experiment compared feathers that had been treated under aerobic or anaerobic conditions with untreated feathers as 25% of the feed protein in the diet. The test diets were fed to growing broiler chicks from Day 6 through Day 21 posthatch. The anaerobically fermented product, feather-lysate, resulted in improved growth responses of 6.9 and 19.3% over the aerobic- and nonbacterial-treated feather feed products, respectively, but 6.4% less than a standard corn-soy-bean-based diet. In a subsequent experiment, 3 or 6% of feather-lysate, untreated feathers, and commercial feather meal were fed to chicks on a basal diet containing only 10% protein. The linear growth response slopes were compared with the slope resulting when chicks were fed diets containing soybean protein in graded levels from 10 to 19% of the total feed. Feather-lystate supplemented with lysine, methionine, and histidine produced a growth curve identical to that of soybean meal. Commercial feather meal supported an improved growth rate over the untreated feathers but significantly less than feather-lysate. These results indicate that the anaerobic fermentation of feathers offers a potential new process for feather waste treatment to provide a nutritious feed protein.