The people who are providing the services should be reporting back to you. What have they said?
If you want large CNBG then feed more and watch the LMB overpopulate. IMO you stocked too many LMB (100 per acre) to sustain a balanced population after 3 years. That is you will have big CNBG and small skinny LMB (and a few very large LMB) over time. That plus additional feeding will lead to large CNBG.