Not a moderator, but I do have a PSSM/IR/PPID mare. And I apologize to the moderators for being OT.
There is a EPSM/PSSM Yahoo group that can give you help and direction. It's similar to this Cushings group. You mentioned that you were out of Vitamin E.....I've found that for my type 2-PSSM mare keeping her on 3 - 4 grams of vitamin E helps keep her moving freely. And, the new hay might be the source of the problem. You might want to soak it to see if that helps the tying up issues. Lots of info on the EPSM/PSSM site.
NE Calif. 2011