Flip side of the coin.
Typically when I have RBT in the pond during the winter, I have an aerator keeping the ice open in front of the feeder. I fed Purina Aquamax 600 all winter long, a 50# bag would last roughly 4-5 weeks. I fed during the middle of the day. I never saw any more or less morts in my pond during a typical winter. Last winter I didn't feed at all and no difference in the amount of dead fish. I always see a few (less than a handful) every Spring.
Does this mean that the fish didn't have problems from eating the food during the winter? Not necessarily, it just means that in my pond I didn't notice anything extraordinary happening. The RBT didn't show much different growth rates between the fed and unfed winters, so I don't know if feeding actually helps or not.