Join Date: Apr 2008
Location: Orange County, NC
Colts this age are notoriously mouthy. In addition to being curious and wanting to play, remember than nibbling/nipping is an instinctive part of horse romance. You do want to alter this behavior early otherwise it will get worse.
We use a combination of things. Keeping a very short lead (as you mention), smacking on the nose (along with "quit"), and using elbows to keep the head away. At that age, keep leading lessons short. We do 5-10 minutes every other day, correct the behavior, and be patient. If you're consistent, they will stop it.
On the sixth day, God created the Quarter Horse.
On the seventh day, he Painted the good ones.