With testing in my pond last year I found that the RBT had the same amount of growth if I didn't feed from ice-on to ice-off.
I don't know if only one winter of testing is enough. I might try it again this year.
RBT at one pound weight at stocking in October grew to between 2# and 3# by late June. That was feeding 50#/month, every month.
I saw approximately the same amount of growth last year when not feeding ice-on to ice-off, same size and amount of trout stocked as the previous year.
When I put trout in the pond at 2# each, and fed 50#/month, they grew to roughly 7# each by the end of June. Half the number of fish stocked, but the same total weight at stocking.