Raptor Hide is not really a useful material as it can only be used to craft three items as a Leatherworker. However it may be valuable depending on the server. Raptor Hide can only be obtained by skinning Raptors that is between level 25-39. It seems that the most effect method for the greatest yield of Raptor Hide is by farming Highland Fleshstalker from the Arathi Highlands. It is known to have a good drop rate.
See below for the exact area to farm Raptor Hide.