Welcome to PB. Lots of knowledgeable folks here who will help you out. I am no expert. Just a data point to ponder. I have a 5 year old pond in Indiana. It freezes over every year and I stop running the feeder roughly Oct-Apr. Feeder keeps them well fed on AquaMax and I go hand feed most nights while they are active. Pond is aerated. I did the usual stocking. Started with FHM + GSH beforehand then 2-3" BG, RES, LMB. My BG are up to a pound now- they are the mass of activity at feeding. I have RES that are over that and several of them are regulars every evening taking pellets. The LMB are around 3 lbs. Haven't caught the biggest ones I see recently, but certainly not over 4 lb. Everyone has apparently spawned every year as there are all sizes - the 10-12" bass are a hoot to watch as they are in a precarious place in the food chain but still like those LMB pellets.
In Northern waters where they really slow down a portion of the year, 8 lbs that fast would take some special steps.