Normally, I would feed Treasure even if he is due to shed any minute, however this shed I decided to skip feeding him to see if its any different. Well, he has been blue for 3 weeks now, and doesn't look like he will shed for at least a week. I doubt this is due to not getting his mousey, but it is definately different!
To answer your question, in my experience, feeding during shed hasn't changed the timing at all. Venus and Treasure both eat (ate in Venus' case =/) during shed with no problems, not sure about Hunter yet hehe.