Abstract: A hydrolyzer system, apparatus, and method for effecting the continuous conversion of offal, feathers, hair, and other keratinaceous material into usable protein products for further commercial usage. The hydrolyzer system includes a feed screw conveyor, transfer conduit, feed substrate expansion chamber, hydrolyzer, product expansion means, and dryer. The hydrolyzer utilizes direct steam injection heat transfer in combination with a feed expansion chamber means and means for agitation and mixing within the hydrolyzer to fluidize a plug of feather feed substrate formed in the transfer conduit by the feed screw conveyor. The apparatus provides a means for heating and fluidizing the feather feed substrate at elevated temperatures while mixing same to effect its hydrolyzation while preventing the escape of back pressure therefrom via a feed substrate plug formed by the feed screw conveyor.