Well there should be a footprint library called Resitor_THT that holds them. (This lib should be added by default. If not please state your kicad version.)
I suspect you use CvPcb to attach a footprint to the resistor symbol. In which case it might be required to setup the filters correctly. Have a look at this FAQ post on to how to assign a footprint to a symbol: How can i assign a footprint to a symbol?
If you are confused about the terminologies symbol and footprint have a look at this: What is the difference between footprints and symbols?