A feather is not one solid piece of “keratin.” This research review explains the shaft, barbs, barbules, follicle, and protein-rich corneous material that make a chicken feather work.

John H. Robinson’s 1913 textbook contains sharp observations about feather structure, tracts, color patterns, and molt—but also terminology and conclusions that modern science has revised.

OvoPro is a precision-fermented ovalbumin ingredient made by engineered yeast—not a plant-based substitute or a complete egg. This review follows the science from gene design and fermentation through filtration, chromatography, drying, allergen labeling, and FDA’s GRAS response.