Whilst it is true that the typical average length of DNA within a human cell is indeed around six feet, it can vary considerably.
It is not unusual to find human cells containing DNA with a total length of between four and five feet and sometimes up to nine feet.
Last week, I viewed some cells where the total length was close to eleven feet (actually 3.26 metres) removed from a perfectly healthy caucasian man.
It's as well to remember that other species may have smaller or larger DNA strands than ourselves. As an example, the length of human DNA is miniscule compared to that of Zea mays (Corn).