Hmm, Steve, you just might have to let them work at their own pace, or offer feed and pollen patties. I have started using hbh, cause I've heard lots of good things about it, but too soon to give results. As long as the hive looks healthy, and the queen is laying, I wouldn't worry too much. The comb could be brown from lots of traffic, it tends to change in color from white to yellow to brown to black with usage and age.