Trout grow amazingly fast on good food, I've stocked 2# trout in October and they were 7# in mid June.
Man, 2# stockers are huge! My biggest stockers are 3/4 to 1# in December.
I'm guessing they don't survive past mid-June for you, just as they die off about a month earlier for me. Do you try to catch & eat as many as possible the last couple of months? What lures work best?
Quick math shows your fish grew about .6 to .7 # per month. My best went from .8 to 3.3 in December - mid May, maybe .5 # per month. You probably feed them better than I do. I stock about 180# RBT total, most smaller fish to hopefully feed my LMB during winter & early spring.