Do feeders concentrate forage fish like shad for bigger predators like largemouth and HSB?

They do if the bait fish like pellets! Most baitfish do.

Shad are not much for pellets but BG , GShiners ,FH and most forage fish are.

That makes sense

One would need an underwater camera to observe what's really going on but from my observations, the Bass will take a pellet over a nice 3" or 4" Bluegill every time. I've seen the Bass swim right by BG and even Gizzard Shad and take the pellet.

Sometimes I throw pellets in the shallows and the GSH will attack them like Piranha, then a trout will streak in, and he ain't after no pellets.