Dwindling petroleum sources and rising levels of non-biodegradable plastic pollution have led researchers to develop sustainable and environmentally friendly alternatives to replace the petroleum-based plastics and composites that are so ubiquitously used today. In this work, chicken feather fibers (CFF), soy protein isolate (SPI), and jute fabric (JF) were used to produce fully green CFF/SPI resins and fully green JF/(CFF/SPI) hybrid composites. The necessity of an external crosslinking reagent was explored through the comparison of glutaraldehyde (GA) crosslinked CFF/SPI resins and JF/(CFF/SPI) composites with their GA-free counterparts. The results suggested that for most properties, GA-free CFF/SPI resins and JF/(CFF/SPI) composites were superior. In the few instances that GA improved properties, the difference was not significant and was further minimized with the addition of CFF. In addition, this work resulted in neat (GA- and CFF-free) SPI resins that differed visually (in color), mechanically, thermally, and spectrally than previous iterations of neat SPI resins. The results suggested that this difference could potentially be due to semi-crystallinity and/or internal crosslinks, possibly derived from the alternative resin preparation.