Yeah, her thyroid was right in the middle of the normal range, so that's not the case.
I am going to take a more aggressive approach. I somehow suspect she is eating her own breakfast and then finishing Luna's when we're not home. I'm going to feed them while I'm still home and then remove any un-eaten food until we're off work.
She's on a duck and potato based food now and even after a week her coat seems way less out of control. It's still shedding quite a bit, but looks much less scruffy. I'm thinking when we get her re-tested that I will inquire about allergy tests, and see if that could let us in on the secret as to why she's so itchy and "sheddy".
It's good to hear that the levels in your pets were just due to muscle exertion. The pit bull in her gives her this tenacity when she plays that usually leaves out her sense of self preservation and she just goes as hard as she can. I think this attitude toward playtime when she was young and spry is maybe what precipitated her stiff joints, much like a retired athlete?
Here's some shots of My BF playing with Suzie in her prime at 3 years old: