I just love pictures of Zero. He's such a cutie
I buy 50 lb compressed bales of timothy, from my local feed store, and my rabbits all like it and eat it well. But quality can vary, so you'll want to make sure it's good. But with your horse experience, you'll be able to pick out a good hay easily.
What stasis is, is a slowdown of the GI tract, which slows the passage of food, and can create harmful bacteria overgrowth, and problems with a rabbits cecotropes. Because of the slowdown and the growth of the bad bacteria, that creates gas and pain, which then stops a rabbit eating. Any painful health problem can create a lack of appetite. So just because a rabbit stops eating, doesn't necessarily mean it has GI stasis yet. Though the lack of appetite can then lead to stasis because the GI tract isn't moving.
With Zero, it seems more to me that some particular food is causing lots of gas, and therefore pain and the reason he then stops eating. But because you've managed to get the gas and pain under control each time, he seems to recover fairly quickly, and doesn't seem to get much of a gut slowdown from it. If you want to read about a general explanation of the function of a rabbits gi tract, look at this link. It explains it pretty well.
http://www.veterinarypartner.com/Content.plx?P=A&S=0&C=0&A=484#.UZ8FPbx7LTo.twitter
I'm really glad he's feeling better. We want our little Zero to be around for a very long time
Hopefully you'll be able to tell right away, whether or not the critical care is causing the continued bloat. I would think that it should only take 2 or 3 days to really notice if there is any difference. If the bloating stops or isn't as bad, then you'll know it's the culprit.