Hall measurements have been made on a series of iron rich nickel ferrites from room temperature to just above the Curie point (575 degrees C). In the majority of samples the measurements indicate a temperature independent carrier concentration which in all cases is significantly less in magnitude than the ferrous content as determined by chemical analysis. The Hall mobilities are small ( approximately 10^-2 cm² V^-1 s^-1 at room temperature) and indicate an activated hopping process with q approximately 0.2 eV as predicted by the Jonker model.