Although some calf feeds are called "creep" feeds, some people use the term creep feed to describe a method of how an animal is fed and not what an animal is fed.
Used in that manner, it means allowing an animal access to free choice feed (whatever feed) while keeping the other animals away.
It is the setting up of a pen that allows the youngster to have access to the feed, but the adults cannot fit through the access door to the feed. Very common with calves, goat kids, or lambs.
Perhaps that is what the owner meant by creep feeding?