Everyone has problems with getting parsnips to germinate that's why we try to do it on damp kitchen roll or in loo rolls or both. Firstly you need fresh seed i.e. purchased this year with this years date on. Secondly they do tend to start a little better with some gentle heat and thirdly be patient. At least by pre chitting you wont end up with big gaps in your growing area where a row has only partially germinated. Good luck
Ian
Ian