Any of those brookies hatchery fish?
I cant speak for MI, but in NY of the remaining 400 Brook Trout lakes and ponds in the Adirondacks that have not been contaminated with trash fish, there are only around 10 lakes with self sustaining Heritage strain Brook trout. Biologist claim Brook trout do best in a mono culture. Most of the remote ponds and lakes I fish are stocked from the air with heritage strain hatchery fish when they are around 4 long. Fishery biologists are working on reclaiming another 35 lakes that they think can become self sustaining again.
I can say, the Brook trout fishery in the Adirondack lakes and ponds is steadily improving, with the recent state record at 6 lbs 1 oz.. We consistently catch Brook trout 12-20. But remember the Brook trout life span is only 4-6 years on avg..