It's probably not this, but always want to throw this out there; Jackson had Lymes disease early 2010 and he randomly started limping. There had been a lot of snow, etc, so I thought maybe he slipped and injured something. It ended up being lymes after doing x-rays, exams, etc, we just did a simple lymes test and that's what it was -- affecting his joints.
Hope Bella feels better soon.
