Natural fibres are green materials and have some advantages i.e. are renewable, reasonably cheap, biodegradable and ecologically freindly. Conversely, composites made of natural fibers can be used as a reinforcement material either long or short forms or recycled fibres. In the production of this NFC materials are made from a combination of natural fibers and polymeric matrice. In this study, thermoplastic-based polypropylene chips composites were produced by making use of pumice stone with different grain structures and chicken feather as reinforcement. In the composite production process hot-pressing machine was used to develop novel composites. Prior to the production process, the pumice stones were determined in the sizes of 0-1mm, 1-2mm and 2-3mm by passing them through a regular sieve. Later, chicken feathers with 0-1 mm granule structure were chopped in a blender and mixed with pumice stones separately. These mixtures were sewn in between polypropylene nonwoven fabrics. The composite plates were obtained by placing polypropylene chips on top and bottom of the sewn fabric. The samples for thermal conductivity tests were cut with a diameter of 28 mm from these plates. And heat conductivities of these samples were tested on the P.A. HILTON LTD. H940. By reinforcement materials such as chicken feather and pumice stone, it is aimed to improve the heat conductivity properties of the produced composites. Overall results showed that an increas in particle size of pumice stone has negative effect on the thermal conductivity of natural fiber composites.