Changes in fish populations based on natural morts (deaths from all sources other than humans/fishing) and reproduction can take a while. From the limited info I would guess that your BG have been eating the food (you can't see it much of the time) and their feeding/eating (improved condition) has increased their spawn - thus the "lots of small/baby BG" but the LMB condition does not reflect the increased forage base yet as the BG are still small (less than 3in). A very important Bill Cody point that is not considered enough - feeding with out maintaining population balance by removal often results in higher biomass of small hungry fish not a population of bigger better conditioned fish.