From my limited experience:
I concur with CJ that if you feed pellets, they will prefer those over anything else. I have suspicion that they will crowd out other types of fish while feeding on pellets. I do not have HSB, so not sure on that type.
I did not feed mine from the stocking in Oct till April, and I believe they did have an impact on the small fish. Keep in mind, that's what I wanted. Now, if the pond freezes over and you don't feed, how long before they switch over to fish and how long the freeze over is, will all change outcomes I'm sure.
I would guess that my stockers were 1/2#, and by spring the majority were 2.5#. How much live feed and it's availability affected their weight gain is unknown.
