It's taken me several days to work through this in my mind and try to come up with "why" and "what's next". I corresponded with a friend whose knowledge and experience I greatly respect and that was a crucial piece of helping me think it through. The whys I came up with:
- he has been living in confined winter quarters with ice, snow or mud for footing for months and this day he could see wide open spaces which were too tempting
- I was leading him on the right, which isn't foreign to him, but apparently is not as solid as leading from the left
- his single rein stop is not as solid as I'd hoped so he blew through his shoulder rather than yielding his hip when he hit the end of the line
- I've gotten lazy about my handling him and he has gotten less respectful of my space
- he's only 2 1/2!
- don't forget how old he is and practice practice practice the basics and be consistent and clear with my expectations of his behavior.
- work more with him from the right
- work more on the hip yields
- look forward to when it dries out so they can all get out in bigger pastures and kick up their heels without danger to me!