Watch out on circling young horses....I usually do just enough to get the response I am looking for. Circling too hard and for too long in one direction and/or too often can damage the legs.
Feed you young horse properly too.
My guys are on either a high quality diet for foals or Ultium. They get dac Bloom and dac Colt Grower. Good quality hay with as much turn-out and pasture as I can provide. I do the Colt Grower for the first 4 yrs, then switch to Total Performance if they are working or dac Bloom and dac Orange if they aren't pushed.