Im hoping others will chime in, but yes, Ive always just stopped everything and switched cold turkey to soaked hay when my IRs appeared in crisis. They get a little pissed but usually their appetites are raging in an insulin spike so the sulking only lasts a short while

Yes, I saw your note abt the unknown treats. Very sorry to hear that. Last year I caught my neighbors feeding raw corn on the cobs snd tomatoes(?) to my two (neighbors had "run out of carrots"). At the boarding barn where one IR lives, I had to plaster signs all over his paddock boards that say "DIABETIC HORSE -- no treats/grain/grass of any kind". The "diabetes" scares people enough that they wont give treats, whereas Ive found the polite "No Treats" signs were ignored.

I dont have any experience with PQ, unfortunately.

Hang in there....
Kerry in NY
Sept 14