EXTREMELY Shy Chinese box turtles

I have six C. flavomarginata which I bought as hatchlings; they are now approx. four inches in length. During the summer they are housed in a 8' X 8' pen, in the winter they are housed in a 4' X 6' pen. They eat worms, super worms, fuzzy mice, snails, banana, melon, tomato, corn, mango and crickets. They are so skittish that as soon as they see me, they run for cover. This makes it difficult for me to ascertain whether they're eating enough. I would think they should be used to me by now but they're not, not by a long shot. The books say they outgoing and personable..I guess what I'm asking is what has your experience with this species been?

Mine are very outgoing, they literally come out to me looking for worms.