Eventually I did get Shamrock moved over...

And he did flourish.  He didn't have access to grass any longer, and started moving better.  He was also getting magnesium and that helped a lot.  He was also terrified.  Scared to enter the barn...scared to enter his stall.  And the first time it rained this is how he stayed...terrified to stand under a roof.

This is what he looked like after a year on grass.  Absolutely wretched.  He was headshy, spooky, and scared of *everything*.  I had to untie him to brush from his shoulders forward, for fear that he would pull back.  Same thing with fly spraying him.  We had a long road ahead of us, and it was going to be very bumpy, and very hilly.