Those bass look a little skinny. See if the different length bass have any different body condition. That will tell you what size forage is predominant in the pond. i.e. if 12" bass are skinny, and 8" bass are fat, then the majority of the forage is about 2"-2.5" in length and the 8" bass are eating most of it, and that doesn't leave enough to grow to 3"-4" so the 12" bass can do well and grow bigger.
The smaller food requires more calories to catch, and remember that not every swipe that a bass makes trying to catch a fish results in a catch, so those are calories expended without anything in return.
Go to this page,
https://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=160456#Post160456 look at post #468638 and click on the link for relative weight chart of LMB, SMB, SB, CC & Brown Bullheads. Then weigh and measure your bass and compare them to the chart.
