A series of low density, highly porous clay/poly(vinyl alcohol) composite aerogels, incorporating keratin fibers derived from chicken feathers, were fabricated via a convenient and eco-friendly freeze drying method. The introduction of keratin fibers improved the mechanical performance, as well as decreased thermal conductivities, allowing these materials to have potential utility in thermal insulation. Different types of bio-fibers have been compared to confirm the unique and important role of keratin fibers; various processing conditions were applied in order to study processing/structure/property relationships in these materials. The mechanical and thermal insulation properties have been demonstrated to increase with amount of keratin fibers. (C) 2018 Elsevier Ltd. All rights reserved.