68 grams isn't too bad. I bought a pastel a few years ago that weighed 42 grams when I got her home. Now she's a big breeder female.
Two of my prima donnas went 6 or 7 weeks without eating, and then suddenly start taking live right before I was about to start stuffing mice down their throats. I've also got one that I assist fed at 9 weeks, who started taking f/t on his own when I offered two weeks later. (But he still won't even look at live).