I hack out a thoroughbred mare once a week. She gets ridden or lead from a ridden horse most days and plays horseball at least once a week in season. She gets no schooling. She is very difficult to keep on the bit, and hates heavy contact on her mouth. She's a bit better in canter and fine galloping. Probably due to the horseball. She's 9ish and ridden in a jointed snaffle, flash and running martingale. She's not mine so I can't change the tack. We hack in company and I probably could find 5 mins to school her in the paddock before we go out. There's no way she will tolerate the sawing at her mouth that I've seen some people do. If I do some tight circles she's ok for the first 10 minutes. She's a typical TB x-racer: not much schooling, spooky, best in company. But generally a lovely ride.