What were the on-ice conditions like around you? If there is or has been heavy fishing pressure, larger bluegills seem to turn off. This is why you hear of really good action in the early and late stages of the frozen water period. I would almost have to think that these larger fish are lethargic, or very weary in some respect from previous fishing pressure.
But, If these fish have been pretty much un-interrupted during the ice period, I would have to image that they would bite given the right presentation. What I would do is downsize presentation size as well as line size. Big gills get big for a reason, they elude getting caught. This may be by biting very light, or just by refusing an offering that does not look natural.
If I am after big gills, and don't want to fool around with smaller ones, i'll search out the lake's holes or basin, for crappies. I have had good luck with locating schools of crappies, and within the group, most times I'll find some "bull" gills. This pattern really seems to work during the mid-season point. I may not catch many bluegills, but the size that I get are very decent. Plus, catching fish is fun, but I like to "troubleshoot" when it comes to fishing. I really enjoy figuring the fish out, and if i don't figure them out, I'll refine my technique until I do make some progress. I just believe that by using the same technique over and over limits a fisherman to the success that they may have that day or in the future.