Join Date: Sep 2011
Location: Germany- but not German =D
A few weeks can be enough.
I was always taight whatever time a horse had off, or slow time, it takes twice as long to build them back up.
It may be muscle, stiffness or avoiding work.
Have you had him checked over, made sure his saddle fit, teeth are in good order etc?
If its work, then I would say its him avoiding it, or a lack of muscle allowing him to go forwards enough to pick up the weight of the forehand and transfer it to the hind.
If he's on your hands too much, try lunging for a week in an outline, to help build him up, then the next week lunge one day, ride the next etc.
Out of curiosity, why do you ride in a bit, or a hackamore, and why don't you bring him round in a hackamore?